Table of Contents

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION
Washington, D.C. 20549

SCHEDULE 14A

Proxy Statement Pursuant to Section 14(a) of
the Securities Exchange Act of 1934 (Amendment No.          )

Table of Contents

Table of Contents

Roberto R. Herencia Executive Chairman of the Board and Chief Executive Officer Alberto J. Paracchini President and Chief Executive Officer	​	April 29, 202026, 2021 Dear Stockholder: You are cordially invited to attend the 20202021 Annual Meeting of Stockholders of Byline Bancorp, Inc. The Annual Meeting will be held virtually through a live webcast on June 9, 20208, 2021 at 8:30 a.m. Central Standard Time, at our offices located at 180 North LaSalle Street, Suite 300, Chicago, Illinois 60601. If you plan to attend in person, please RSVP by sending an email to acasanueva@bylinebank.com.Daylight Time. The attached Notice of Meeting and Proxy Statement describe the formal business to be conducted at the Annual Meeting. Members of our Board of Directors and executive officers will be present in person or by telephonevirtually at the Annual Meeting to respond to any questions that our stockholders may have. * We intend to hold our Annual Meeting in person. However, we are actively monitoring the coronavirus (COVID-19) situation and are sensitive to the public health and travel concerns our stockholders may have and the protocols that federal, state, and local governments have imposed. In the event it is not possible or advisable to hold our Annual Meeting in person, we will announce alternative arrangements for the meeting as promptly as practicable, which may include holding the meeting solely by means of remote communication. If we take this step, we will announce the decision to do so in advance, and details on how to participate will be posted atwww.bylinebancorp.com. If you are planning to attend the meeting, please check the website one week prior to the meeting date. As always, we encourage you to vote your shares prior to the Annual Meeting. Your vote is important. Whether or not you plan to attend the Annual Meeting virtually, please vote as soon as possible to ensure that your shares are represented and voted at the meeting. Our Board of Directors has determined that the proposals to be considered at the Annual Meeting as described in the attached Notice of Meeting and Proxy Statement are in the best interests of Byline Bancorp and its stockholders.For the reasons set forth in the Proxy Statement, the Board of Directors unanimously recommends a vote "FOR" each proposal to be considered. On behalf of the Board of Directors and the officers and employees of Byline Bancorp, we would like to take this opportunity to thank our stockholders for their continued support. Sincerely,
	​		​
	​	Roberto R. Herencia Executive Chairman of the Board and Chief Executive Officer	​	Alberto J. Paracchini President and Chief Executive Officer

Table of Contents

Notice of Annual Meeting of Stockholders of Byline Bancorp, Inc.

		Items of Business
				To elect the nineeight director nominees named in the accompanying proxy statement to the Board of Directors of the Company, each to serve until the 20212022 Annual Meeting of Stockholders or until their successors are duly elected and qualified;
				To ratify the appointment of Moss Adams LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2020;2021; and
				To consider such other business that may properly come before the Annual Meeting, or any adjournment thereof, by or at the direction of the Board of Directors.
​	​	​	​	​
		Every Vote is Important

 

		Internet Visit the website noted on your proxy card to vote online.		Telephone Use the toll-free telephone number on your proxy card to vote by telephone.		Vote by Mail Sign, date, and return your proxy card in the enclosed envelope to vote by mail.
		A list of stockholders entitled to vote at the meeting will be available for inspection at the Company's main office located at 180 North LaSalle Street, Suite 300, Chicago, Illinois 60601 the day of the Annual Meeting and for a period of ten days prior to the meeting.Annual Meeting and will also be made available virtually at the Annual Meeting itself for examination by any stockholder upon request. We are taking advantage of the Securities and Exchange Commission's rules that allow companies to furnish proxy materials to stockholders via the Internet. We sent a Notice of Internet Availability of Proxy Materials to holders of our common stock as of the record date on or about April 29, 2020.26, 2021. The Notice describes how you can access our proxy materials, including this proxy statement, beginning on April 29, 2020.26, 2021.

WHETHER OR NOT YOU EXPECT TO ATTEND THE ANNUAL MEETING, PLEASE SUBMIT YOUR PROXY WITH VOTING INSTRUCTIONS. YOU MAY VOTE BY TELEPHONE, VIA THE INTERNET OR BY MAIL.

* We intend to hold our Annual Meeting in person. However, we are actively monitoring the coronavirus (COVID-19) situation and are sensitive to the public health and travel concerns our stockholders may have and the protocols that federal, state, and local governments have imposed. In the event it is not possible or advisable to hold our Annual Meeting in person, we will announce alternative arrangements for the meeting as promptly as practicable, which may include holding the meeting solely by means of remote communication. If we take this step, we will announce the decision to do so in advance, and details on how to participate will be posted atwww.bylinebancorp.com. If you are planning to attend the meeting, please check the website one week prior to the meeting date. As always, we encourage you to vote your shares prior to the Annual Meeting.

	​	BY ORDER OF THE BOARD OF DIRECTORS,
	​	By	​
Chicago, Illinois April 29, 202026, 2021	​	Roberto Herencia Executive Chairman of the Board and Chief Executive Officer

Table of Contents

TABLE OF CONTENTS

Table of Contents

PROXY STATEMENT
FOR THE 20202021 ANNUAL MEETING OF STOCKHOLDERS
TO BE HELD ON JUNE 9, 20208, 2021

The enclosed proxy is solicited on behalf of the board of directors (the "Board of Directors" or the "Board") of Byline Bancorp, Inc., a Delaware corporation (the "Company"), which is a registered bank holding company that owns and operates Byline Bank (the "Bank"), for use at the 20202021 Annual Meeting of Stockholders (the "Annual Meeting") to be held virtually on June 9, 20208, 2021 at 8:30 a.m. Central Standard Time at the Company's offices located at 180 North LaSalle Street, Suite 300, Chicago, Illinois.Daylight Time. This proxy statement (this "Proxy Statement"), together with the Notice of Annual Meeting and proxy card, is first being made available to stockholders on or about April 29, 2020.26, 2021.

Unless we state otherwise or the context otherwise requires, references in this Proxy Statement to "Byline," "we," "our," "us," "ourselves," "the company" and "the Company" refer to Byline Bancorp, Inc., a Delaware corporation, and its consolidated subsidiaries.

Important Notice Regarding the Availability of Proxy Materials for the
Stockholder Meeting to be Held on June 9, 20208, 2021

Pursuant to rules of the Securities and Exchange Commission (the "SEC"), we have elected to provide access to our proxy materials via the Internet. Accordingly, we sent a Notice of Internet Availability of Proxy Materials (the "Notice") to our stockholders. The Notice provides stockholders with instructions on how to access and review this Proxy Statement and our 20192020 Annual Report online, as well as vote online. We, like many public companies, have determined that providing proxy materials electronically significantly reduces our printing and mailing costs associated with the distribution of printed copies of our proxy materials to our stockholders.

Stockholders who receive athe Notice will not receive a printed copy of the proxy materials by mail unless you request one. All stockholders will have the ability to access the proxy materials on the website referred to in the Notice or request to receive a printed set of the proxy materials. Instructions on how to access the proxy materials via the Internet or to request printed copies may be found within the Notice. In addition, stockholders may request to receive proxy materials in printed form by mail or electronically by email on an ongoing basis.

YOUR VOTE IS IMPORTANT

Please vote via the Internet, Telephone or telephone.Mail.

Internet: www.voteproxy.comwww.proxyvote.com
Phone: Phone: In the U.S., call toll-free 1-800-PROXIES (1-800-776-9437), or
Outside the U.S., call 1-718-921-85001-800-690-6903 and follow the instructions

If you are voting by mailing your proxy card, please mark, sign and date the proxy card when received and return it promptly in the self-addressed, stamped envelope whichthat we have provided.

* We intend to hold our Annual Meeting in person. However, we are actively monitoring the coronavirus (COVID-19) situation and are sensitive to the public health and travel concerns our stockholders may have and the protocols that federal, state, and local governments have imposed. In the event it is not possible or advisable to hold our Annual Meeting in person, we will announce alternative arrangements for the meeting as promptly as practicable, which may include holding the meeting solely by means of remote communication. If we take this step, we will announce the decision to do so in advance, and details on how to participate will be posted atwww.bylinebancorp.com. If you are planning to attend the meeting, please check the website one week prior to the meeting date. As always, we encourage you to vote your shares prior to the Annual Meeting.

Table of Contents

About the Meeting

What is the date, time and place of the Annual Meeting?

Our 20202021 Annual Meeting of Stockholders will be held on Tuesday, June 9, 2020,8, 2021, beginning at 8:30 a.m., Central StandardDaylight Time, virtually at the Company's offices located at 180 North LaSalle Street, Suite 300, Chicago, Illinois 60601.www.virtualshareholdermeeting.com/BY2021

What is the purpose of the Annual Meeting?

At the Annual Meeting, stockholders will act upon the matters outlined in the Notice of Meeting on the cover page of this Proxy Statement, consisting of:

(1)

the election of the nineeight director nominees named in this Proxy Statement to the Board of Directors, each to serve until the 20212022 Annual Meeting of Stockholders or until their successors are duly elected and qualified;



(2)

the ratification of the appointment of Moss Adams LLP as the Company's independent registered public accounting firm for the fiscal year ending December 31, 2020;2021; and



(3)

the consideration of such other matters as may properly come before the meeting.

Why did I receive a notice in the mail regarding the availability of proxy materials on the Internet instead of a full set of proxy materials?

Pursuant to rules of the SEC, we have elected to provide access to our proxy materials via the Internet. Accordingly, we sent a Notice of Internet Availability of Proxy Materials (the "Notice") to our stockholders. The Notice provides stockholders with instructions on how to access and review this Proxy Statement and our 20192020 Annual Report online, as well as vote online. We, like many public companies, have determined that providing proxy materials electronically significantly reduces our printing and mailing costs associated with the distribution of printed copies of our proxy materials to our stockholders.

Stockholders who receive a Notice will not receive a printed copy of the proxy materials by mail unless you request one. All stockholders will have the ability to access the proxy materials on the website referred to in the Notice or request to receive a printed set of the proxy materials. Instructions on how to access the proxy materials via the Internet or to request printed copies may be found within the Notice. In addition, stockholders may request to receive proxy materials in printed form by mail or electronically by email on an ongoing basis.

Who is entitled to vote at the Annual Meeting?

Only our stockholders of record at the close of business on April 23, 2020,14, 2021, the record date for the meeting, are entitled to receive notice of and to participate in the Annual Meeting. If you were a stockholder of record on that date, you will be entitled to vote all of the shares you held on that date at the meeting, or any postponement(s) or adjournment(s) of the meeting. As of the record date, there were 38,501,50738,632,697 shares of common stock outstanding, all of which are entitled to be voted at the Annual Meeting. As of the record date, there were 39,106,222 shares of common stock issued.

A list of stockholders will be available at our offices at 180 North LaSalle Street, Suite 300, Chicago, Illinois 60601 for a period of ten days prior to the Annual Meeting and will also be made available virtually at the Annual Meeting itself for examination by any stockholder.

What are the voting rights of the holders of our common stock?

Holders of our common stock are entitled to one vote per share on each matter that is submitted to stockholders for approval. Stockholders do not have cumulative voting rights.

2    Byline Bancorp, Inc.  20202021 Proxy Statement

Table of Contents

Who can attend the meeting?

All stockholders as of the record date, or their duly appointed proxies, may virtually attend the Annual Meeting.Please also note that if you hold your shares in "street name" (that is, through a broker or other nominee) and plan to attend the Annual Meeting, you will need to bring a copy of a brokerage statement reflecting your stock ownership as of the record date in order to vote your shares at the meeting. If you plan to attend in person, please also RSVP by sending an email to acasanueva@bylinebank.com indicating your intention to attend the Annual Meeting.

What constitutes a quorum?

The presence at the meeting, in person (virtually) or by proxy, of the holders of common stock representing a majority of the combined voting power of the outstanding shares of common stock on the record date will constitute a quorum, permitting the meeting to conduct its business. As of the record date, there were 38,501,50738,632,697 shares of common stock outstanding, all of which are entitled to be voted at the Annual Meeting.

What vote is required to approve each item?

The votes required to approve the matters to be presented at the Annual Meeting as listed in the Notice of the Annual Meeting are as follows:

•

For purposes of electing directors at the Annual Meeting, directors will be elected by a plurality of the votes of the shares virtually present in person(virtually) or represented by proxy at the meeting and entitled to vote on the election of directors. Accordingly, the director nominees receiving the most votes of the holders of our common stock will be elected as directors.

•

For all other matters, including the ratification of the appointment of Moss Adams LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2020,2021, approval requires the affirmative vote of the holders of a majority of the shares present in person (virtually) or represented by proxy at the Annual Meeting and entitled to vote.

For purposes of Proposal 2, proxies received but marked as abstentions will be included in the calculation of the number of shares considered to be present at the meeting for purposes of determining a quorum. Pursuant to our By-laws, broker non-votes will not be counted as shares entitled to vote at the meeting, but votes cast "for" or "against" and abstentions with respect to all matters will be counted as shares entitled to vote. A "broker non-vote" will occur when a nominee holding shares for a beneficial owner does not vote on a particular proposal because the nominee does not have discretionary power with respect to that proposal and has not received instructions from the beneficial owner. On matters other than the election of directors, abstentions will be treated as a vote "against". If less than a majority of the combined voting power of the outstanding shares of common stock is represented at the Annual Meeting, either the Chairperson of the meeting or a majority of the shares so represented may adjourn the Annual Meeting from time to time without further notice.

The inspector of election for the Annual Meeting will determine the number of shares of common stock represented at the meeting, the existence of a quorum and the validity and effect of proxies, and shall count and tabulate ballots and votes and determine the results thereof.

Please note that if you hold your shares in "street name," your bank, broker or other nominee will not be permitted to vote your shares on Proposal 1 (election of directors) absent specific instructions from you. Therefore, it is important that you follow the voting instructions on the form that you receive from your bank, broker or other nominee.

What are the Board's recommendations?

Our Board of Directors recommends a vote FOR the election of all of the respective nominees for director named in this Proxy Statement and FOR the ratification of the appointment of Moss Adams LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2020.2021.

Byline Bancorp, Inc.  2020 Proxy Statement    3

Table of Contents

Unless contrary instructions are indicated on your proxy, all shares represented by valid proxies received pursuant to this solicitation (and which have not been revoked in accordance with the procedures set forth below) will be voted (1) FOR the election of each of the respective nominees for director named in this Proxy Statement; (2) the ratification of the appointment of Moss Adams LLP as our independent registered public accounting firm for the fiscal year ending December 31, 2020;2021; and (3) in accordance with the recommendation of our Board of Directors, FOR or AGAINST all other matters as may properly come before the Annual Meeting. In the event a stockholder

Byline Bancorp, Inc.  2021 Proxy Statement    3

Table of Contents

specifies a different choice by means of the proxy, such shares will be voted in accordance with the specification made.

How do I vote?

If you are a holder of record (that is, if your shares are registered in your own name with our transfer agent), you may vote using the proxy card contained in the proxy materials. Voting instructions are provided on the proxy card. The Notice also includes information about how to vote via the Internet (atwww.voteproxy.comwww.proxyvote.com) or via telephone (in the U.S, call toll-free 1-800-PROXIES (1-800-776-9437), or outside the U.S., call 1-718-921-8500(1-800-690-6903 and follow the instructions).

If you are a street name holder (that is, if you hold your shares through a bank, broker or other holder of record), you must provide your voting instructions in accordance with the voting instruction form provided by your bank, broker or other holder of record, who will then vote your shares on your behalf. The availability of telephone or Internet voting will depend upon your bank's, broker's, or other holder of record's voting process.

If you virtually attend the Annual Meeting, you can of course, vote in person.If you are a street name holder and wish to vote at the meeting, you must first obtain a proxy from your bank, broker or other holder of record authorizing you to vote your shares at the meeting.that time.

Can I change my vote?

Yes. The giving of a proxy does not eliminate the right to vote in personat the Annual Meeting should any stockholder giving the proxy so desire. Stockholders have an unconditional right to revoke their proxy at any time prior to the exercise of that proxy, by (1) voting in person at the Annual Meeting, or (2) by filing a written revocation or duly executed proxy bearing a later date with our Secretary.

Who pays for costs relating to the proxy materials and Annual Meeting?

The costs of preparing, assembling, providing access to and mailing this Proxy Statement, the Notice of Annual Meeting of Stockholders and the Annual Report and proxy card, along with the cost of posting the proxy materials on a website, are to be borne by us. In addition to the use of mail, our directors, officers and employees may solicit proxies personally and by telephone, facsimileemail and other electronic means. They will receive no compensation in addition to their regular salaries. We may request banks, brokers and other custodians, nominees and fiduciaries to forward copies of the proxy materials to their principals and to request authority for the execution of proxies. We may reimburse these persons for their expenses in so doing, if applicable.

4    Byline Bancorp, Inc.  20202021 Proxy Statement

Table of Contents

Stock Ownership

Security Ownership of Certain Beneficial Owners and Management

The following table shows information regarding the beneficial ownership of our common stock for the following:

•

each stockholder known by us to beneficially own more than 5% of our common stock;

•

each of our directors;

•

each of our named executive officers; and

•

all directors and executive officers as a group.

•

All information is as of the record date, except as noted otherwise.

Beneficial ownership is shown as of April 23, 2020,14, 2021, and is based on 38,501,50738,632,697 shares of our common stock outstanding as of April 23, 2020.14, 2021. Beneficial ownership is determined in accordance with the rules of the SEC, which generally attribute beneficial ownership of securities to persons who possess sole or shared voting power or investment power with respect to such securities. A security holder also is deemed to be, as of any date, the beneficial owner of all securities that such security holder has the right to acquire within 60 days after such date, such as through the exercise of options or warrants or the conversion of a security. Except as otherwise indicated, all persons listed below have sole voting and investment power with respect to the shares beneficially owned by them. Except as otherwise indicated, the address for each stockholder listed below is c/o Byline Bancorp, Inc., 180 North LaSalle Street, Suite 300, Chicago, Illinois 60601.

Byline Bancorp, Inc.  2020 Proxy Statement    5

Table

Byline Bancorp, Inc.  2021 Proxy Statement    5

Table of Contents

6    Byline Bancorp, Inc.  2020 Proxy Statement

Table of Contents

Delinquent Section 16(a) Reports

Section 16(a) of the Securities Exchange Act of 1934, as amended (the "Exchange Act"), requires our directors and executive officers, and persons owning more than 10% of a registered class of our equity securities, to file with the SEC reports of ownership and changes in ownership of the Company's equity securities. These same persons are also required to furnish us with copies of all such forms. Based solely on a review of the copies of the forms furnished to us, or written representations that no Form 5 filings were required, we believe that, with respect to the 20192020 fiscal year, all required Section 16(a) filings were timely made, with the exception of a Form 3 filed for Steven P. Kent on June 18, 2019, and a Form 4 for Thomas Abraham filed on January 6, 2020, reflecting a restricted stock award granted to him on December 19, 2019.made.

6    Byline Bancorp, Inc.  20202021 Proxy Statement    7

Table of Contents

	Proposal 1 Election of Directors The Governance and Nominating Committee of the Board of Directors is responsible for making recommendations to our Board of Directors regarding candidates for directorships and the size and composition of our Board of Directors. Each of our nominees currently serves as a Byline director, and has consented to being named in this Proxy Statement and has agreed to serve if elected. If any nominee becomes unable to serve, the shares represented by all valid proxies will be voted for the election of such substitute nominees as the Board of Directors may recommend. At this time, the Board of Directors knows of no reason why any nominee might be unavailable or unwilling to serve.

The table below sets forth information regarding each nominee for director. Currently, each of our directors is elected annually to serve a one yearone-year term.

Information Regarding Nominees for Election

8    Byline Bancorp, Inc.  20202021 Proxy Statement    7

Table of Contents

8    Byline Bancorp, Inc.  20202021 Proxy Statement    9

Table of Contents

10    Byline Bancorp, Inc.  20202021 Proxy Statement    9

Table of Contents

10    Byline Bancorp, Inc.  20202021 Proxy Statement    11

Table of Contents

12    Byline Bancorp, Inc.  2020 Proxy Statement

Table of Contents

THE BOARD OF DIRECTORS UNANIMOUSLY RECOMMENDS A VOTE"FOR" THE ELECTION OF EACH NOMINEE FOR DIRECTOR UNDER PROPOSAL 1

AppointmentRetirement of Robert R. Yohanan tofrom Byline's and Byline Bank's Board of Directors

On May 30, 2018, the Board of Directors appointed Robert R. Yohanan, who at that time was First Evanston'sthe Chief Executive Officer of First Evanston Bancorp, Inc. and First Bank & Trust (collectively, "First Evanston"), to the Board of Directors of Byline, to be effective upon completion of the merger of First Evanston with Byline. The appointment of Mr. Yohanan was contemplated by and made in accordance with the merger agreement.

Also in connection with the execution of the merger agreement, we entered into a services and covenant agreement (the "services agreement") with Mr. Yohanan, which superseded his then existing employment agreement and change in control agreement with First Evanston upon the effective time of the merger. The agreement providesprovided that Mr. Yohanan's employment with First Evanston terminated upon the effective time of the merger and, for the period from the effective time of the merger until the third anniversary thereof, Mr. Yohanan willwas to provide general advisory services and be available to consult on specific projects with respect to Byline's business and the integration of Byline and First Evanston as requested by the Chief Executive Officer of Byline.

In addition, pursuant to the services agreement, during such three-year period, Mr. Yohanan will serveserved three one-year terms (or until our 2021 Annual Meeting of Stockholders in 2021)Meeting) as a member of the boards of directors of Byline (subject to election by Byline's stockholders at our 2020 Annual Meeting of Stockholders) and Byline Bank. Accordingly, we appointed Mr. Yohanan will retire from his positions on the Board and Committees of Byline Bank effective upon the expiration of his current term as a director upon the closing of the merger for a term that initially expired at the 2019 Annual Meeting. He was nominated and re-elected at our 2019 Annual Meeting to serve a one-year term that expires at our 2020 Annual Meeting., We re-nominated Mr. Yohanan to the Board in 2020, subject to election by our stockholders at our 2020 Annual Meeting.on June 8, 2021.

Byline Bancorp, Inc.  20202021 Proxy Statement    1311

Table of Contents

Board of Directors; Board Meetings; Committees And MembershipCorporate Governance

Composition of Our Board of Directors

Our Board of Directors currently has nineeight members. Under our Amended and Restated Certificate of Incorporation and By-Laws, the number of directors constituting our Board of Directors is fixed from time to time by resolution of the Board of Directors. The Board met seven14 times during 2019.2020. There are no family relationships among any of our directors and executive officers.

Board Leadership Structure Qualifications and DiversityQualifications

We believe that our directors should have the highest professional and personal ethics and values, consistent with our longstanding values and standards. They should have broad experience at the policy making level in business, government, or banking. They should be committed to enhancing stockholder value and should have sufficient time to carry out their duties and to provide insight and practical wisdom based on experience. Each director must represent the interests of all stockholders.

When considering potential director candidates, our Board of Directors considers the candidate's character, judgment, diversity, skills, including financial literacy, and experience in the context of our needs and those of the Board of Directors. Our Board also considers the candidate's service on boards of other companies and whether such service would impair the candidate's ability to perform responsibly all director duties for Byline. Our Board believes that a range of experience, knowledge and judgment, as well as a diversity of perspectives, geographic regions, gender, race and national origin on the Board, enhances the overall effectiveness of the Board.

Our Board of Directors does not have a formal policy requiring the separation of the roles of Chief Executive Officer and Chairman of the Board. It is the Board of Directors' view that rather than having a rigid policy, the Board of Directors, with the advice and assistance of the Governance and Nominating Committee, and upon consideration of all relevant factors and circumstances, will determine, as and when appropriate, whether the two offices should be separate. Currently, our leadership structure separatesMr. Herencia holds the officescombined positions of Chief Executive Officer and Chairman of the Board with Mr. Paracchini serving as ourand Chief Executive Officer, while Mr. Paracchini is President of the Company, as well President and Chief Executive Officer of Byline Bank. Also, Mr. del Valle Perochena was appointed Lead Director of the Company in February 2021 upon the assumption by Mr. Herencia of the Executive Chairman and Chief Executive Officer roles. We believe this current structure provides the appropriate level of oversight and management, as Chairmanwell as intends to accelerate and support the execution of the Company's strategic plan, specifically its growth strategy, as a leading commercial bank in the Chicago MSA.

Diversity

Our Board believes that a range of experience, knowledge, and judgement, as well as a diversity of perspectives, geographic regions, gender, race, and national origin on the Board, enhances the overall effectiveness of the Board. At present, 56% of our Board is diverse from a gender, race, or ethnic perspective. During 2020, the Company focused its Diversity, Equity, and Inclusion (DEI) initiatives to ensure we are doing the work necessary to make the Company a safe and welcoming place for all of our employees and customers. With the support of the Board, reinforcing the leadership role ofCompany appointed a DEI Council as the foundation and catalyst for honoring our Board of Directors in its oversight ofemployees, engaging our customers and community, creating a great place to work, and ultimately driving business and affairs.success.

Director Independence

Under the rules of the New York Stock Exchange ("NYSE"), independent directors must comprise a majority of our Board of Directors. The rules of the NYSE, as well as those of the SEC, impose several requirements with respect to the independence of our directors. Our Board of Directors has undertaken a review of the independence of each director in accordance with these rules. Based on information provided by each director concerning his or her background, employment and affiliations, our Board of Directors has determined that each of Roberto R. Herencia, Phillip R. Cabrera, Antonio del Valle Perochena, Mary Jo S. Herseth, Steven P. Kent, William G. Kistner, Antonio del Valle Perochena,and Steven M. Rull and Steven P. Kent do not have relationships that would interfere with the exercise of their independent judgment in carrying out the responsibilities of a director and that each of these directors is "independent" as that term is defined under the applicable rules. Our Board of Directors has determined that Messrs. del Valle Perochena, Cabrera and Kent also satisfy the heightened independence requirements for compensation committee members, and that Messrs. Rull,

12    Byline Bancorp, Inc.  2021 Proxy Statement

Table of Contents

Kistner and Cabrera also qualify as independent directors under the heightened independence requirements of Rule 10A-3 of the Exchange Act for members of the audit committee. In making these determinations, our Board of Directors considered the current and prior relationships that each non-employee director has with our company and certain other facts and circumstances our Board of Directors deemed relevant in determining their independence, including the beneficial ownership of our capital stock by each non-employee director.

Committees of Our Board of Directors

The standing committees of our Board of Directors consist of an Audit Committee, a Compensation Committee, a Governance and Nominating Committee and a Risk Committee. The responsibilities of these committees are described below. Our Board of Directors may also establish such other committees as it deems appropriate, in

14    Byline Bancorp, Inc.  2020 Proxy Statement

Table of Contents

accordance with applicable law and regulations and our corporate governance documents. The following table summarizes the current membership of each of the committees of the Board of Directors. Ms. Herseth serves as a member of the Executive Credit, ALCO and Trust Committees of the Board of Directors of Byline Bank. Mr. Yohanan serves as a member of the Trust and ALCO Committees of the Board of Directors of Byline Bank. Mr. Kent serves as a member of the risk, compensation, governance and nominating and ALCO Committees of the Board of Directors of Byline Bank.

· Membero Chair

Byline Bancorp, Inc.  2021 Proxy Statement    13

Table of Contents

Audit Committee

The Audit Committee assists the Board of Directors in fulfilling its responsibilities for general oversight of the integrity of our financial statements, our compliance with legal and regulatory requirements, the independent auditors' qualifications and independence, the performance of our internal audit function and independent auditors and risk assessment and risk management.

The Audit Committee works closely with management as well as our independent auditors. The Audit Committee has the authority to obtain advice and assistance from, and receive appropriate funding to engage outside legal, accounting or other advisors as the Audit Committee deems necessary to carry out its duties. The Audit Committee has adopted a written charter that among other things, specifies the scope of its rights and responsibilities. A copy of the committee's charter is available on our website atwww.bylinebancorp.com under the "Governance Documents" tab.

Byline Bancorp, Inc.  2020 Proxy Statement    15

Table of Contents

The Audit Committee is composed solely of members who satisfy the applicable independence, financial literacy and other requirements of the NYSE for audit committees, and at least one of its members is an "audit committee financial expert" as defined by the rules of the SEC, which is Mr. Kistner. Messrs. Rull, Kistner and Cabrera also meet the heightened independence requirements of Rule 10A-3 of the Exchange Act. The Audit Committee held

14    meetings in 2019.Byline Bancorp, Inc.  2021 Proxy Statement

Table of Contents

Compensation Committee

The Compensation Committee sets and administers the policies that govern our executive compensation programs and is responsible for discharging the Board's responsibilities relating to compensation of our executive officers and directors.

Under the Compensation Committee's charter, the Compensation Committee may, at its discretion, delegate all or a portion of its duties and responsibilities to a subcommittee of the Compensation Committee. In addition, it may delegate authority to the Chief Executive Officer to approve compensation applicable to non-executive level Company employees, provided that the Compensation Committee reviews and approves the Company's compensation structures applicable to non-executive level employees on an annual basis.

In 2019,2020, the Compensation Committee retained Pearl Meyer & Partners, LLC ("Pearl Meyer") primarily to assist the Compensation Committee in determining and structuring executive compensation and to assess the market competivenesscompetitiveness of the Company's executive compensation program. The Compensation Committee has annually engaged Pearl Meyer for these and related services since 2014. With respect to any advice provided to the Committee by Pearl Meyer, the Compensation Committee received a letter from Pearl Meyer addressing factors relevant to SEC and NYSE rules regarding independence and conflicts of interest. After considering the information provided by Pearl Meyer and other factors, no conflicts of interest with respect to Pearl Meyer were identified by the Compensation Committee, and the Compensation Committee concluded that Pearl Meyer was an independent consultant.

16    Byline Bancorp, Inc.  2020 Proxy Statement

Table of Contents

The Compensation Committee has adopted a written charter that among other things, specifies the scope of its rights and responsibilities. A copy of the committee's charter is available on our website atwww.bylinebancorp.com under the "Governance Documents" tab. The Compensation Committee is composed solely of members who satisfy the applicable independence requirements of the NYSE as they apply to members of compensation committees. The Compensation Committee held four meetings in 2019.

Byline Bancorp, Inc.  2021 Proxy Statement    15

Table of Contents

Governance and Nominating Committee

The Governance and Nominating Committee is responsible for making recommendations to our Board of Directors regarding candidates for directorships and the size and composition of our Board of Directors. In addition, the Governance and Nominating Committee is responsible for overseeing our corporate governance guidelines and reporting and making recommendations to our Board of Directors concerning governance matters.

The Governance and Nominating Committee has adopted a written charter that among other things, specifies the scope of its rights and responsibilities. A copy of the Committee's charter, as well as a copy of the corporate governance guidelines is available on our website at www.bylinebancorp.com under the "Governance Documents" tab. The Governance and Nominating Committee is composed solely of members who satisfy the applicable independence requirements of the NYSE for governance and nominating committees. The Governance and Nominating Committee held three meetings in 2019.

Risk Committee

The Risk Committee is responsible for overseeing our enterprise risk management policies, commensurate with our capital structure, risk profile, complexity, size and other risk related factors.

Byline Bancorp, Inc.  2020 Proxy Statement    17

Table of Contents

​

The Risk Committee has adopted a written charter that specifies among other things, the scope of its rights and responsibilities. The Risk Committee held eight meetings in 2019.A copy of the committee's charter is available on our website at www.bylinebancorp.com under "Goverrnance Documents" tab.

In addition to the committees described above, the Board of Directors of Byline Bank also has an Executive Credit Committee, a Trust Committee and an ALCO Committee. The Executive Credit Committee provides oversight of our credit risk management function. This committee oversees the risk appetite, the development of policies, practices

16    Byline Bancorp, Inc.  2021 Proxy Statement

Table of Contents

and systems for measuring credit risk and monitors the performance and quality of our credit portfolio. Mr. CabreraMs. Herseth is Chairman of the Executive Credit Committee, and the committee's other members include Messrs. Herencia, Paracchini, Kent and Ms. Herseth.Cabrera. The Trust Committee provides oversight in implementing policies for the Bank's Wealth Management and Trust department, as well as practices and controls sufficient to promote high quality fiduciary administration. Mr. Rull is Chairman of the Trust Committee, and the committee's other members include Messrs. Cabrera, Herencia Yohanan and Ms. Herseth. The ALCO Committee provides oversight of the Asset and Liability Management function. Mr. Rull is the Chairman of the ALCO Committee, and the committee's other members include Messrs. Herencia, Kent, Cabrera, Yohanan, Paracchini and Ms. Herseth.

Board Oversight of Risk Management

Our Board of Directors believes that effective risk management and control processes are critical to our safety and soundness, our ability to predict and manage the challenges that we face and, ultimately, our long termlong-term corporate success. Our Board of Directors, both directly and through its committees, including the Risk Committee, is responsible for overseeing our risk management processes, with each of the committees of our Board of Directors assuming a different and important role in overseeing the management of the risks we face.

The Risk Committee of our Board of Directors oversees our enterprise wideenterprise-wide risk management framework, which establishes our overall risk appetite and risk management strategy and enables our management to understand, manage and report on the risks we face. Our Risk Committee also reviews and oversees policies and practices established by management to identify, assess, measure and manage key risks we face, including the risk appetite metrics developed by management and approved by our Board of Directors. The Audit Committee of our Board of Directors is responsible for overseeing risks associated with financial matters (particularly financial reporting, accounting practices and policies, disclosure controls and procedures and internal control over financial reporting) and engaging as appropriate with our Risk Committee to assess our enterprise wideenterprise-wide risk framework. The Compensation Committee of our Board of Directors has primary responsibility for risks and exposures associated with our compensation policies, plans and practices, regarding both executive compensation and the general compensation structure generally.structure. In particular, our Compensation Committee, in conjunction with our President and Chief Executive Officer, andPresident, Chief Human Resources Officer and other members of our management as appropriate, reviews our incentive compensation arrangements to ensure these programs are consistent with applicable laws and regulations, including safety and soundness requirements, and do not encourage imprudent or excessive risk taking by our employees. The Governance and Nominating Committee of our Board of Directors oversees risks associated with the independence of our Board of Directors and potential conflicts of interest.

Our senior management is responsible for implementing and reporting to our Board of Directors regarding our risk management processes, including by assessing and managing the risks we face, including strategic, operational, regulatory, investment and execution risks, on a day to day basis. Our senior management is also responsible for creating and recommending to our Board of Directors for approval appropriate risk appetite metrics reflecting the aggregate levels and types of risk we are willing to accept in connection with the operation of our business and pursuit of our business objectives.

The role of our Board of Directors in our risk oversight is consistent with our leadership structure, with our President and Chief Executive Officer, President, Chief Financial Officer and the other members of senior management having responsibility for assessing and managing our risk exposure, and our Board of Directors and its committees providing oversight in connection with those efforts. We believe this division of risk management responsibilities presents a consistent, systemic and effective approach for identifying, managing and mitigating risks throughout our operations.

Stockholder Engagement and Communicating with Our Board

We believe in proactive and transparent communication and engagement with our stockholders to promote an understanding of the values we maintain, our governance framework, the decisions we make and how me make

18    Byline Bancorp, Inc.  2020 Proxy Statement

Table of Contents

them, our business strategy and our financial performance, and we welcome receiving communications from our stockholders regarding these matters. Generally, the Board relies on the Executive Chairman of the Board theand Chief Executive Officer, and other executive officers to speak for the Company, and management is generally responsible for managing our corporate communications and investor relations activities. Throughout the year, our Executive

Byline Bancorp, Inc.  2021 Proxy Statement    17

Table of Contents

Chairman and Chief Executive Officer, President and Chief Financial Officer regularly interact with significant stockholders regarding our performance, business strategy and other corporate matters. From time to time, it may be appropriate for one or more of our non-executive directors to speak or meet with stockholders. Any such communication would occur under the direction and oversight of the Chairman.Executive Chairman and Chief Executive Officer.

Stockholders may contact the Board or any committee of the Board about governance-related and executive compensation matters, or other matters specific to the Board's and/or its committees' oversight responsibilities. Written correspondence may be directed to the Board of Directors at Byline Bancorp, Inc., Attention: Corporate Secretary, 180 North LaSalle Street, Suite 300, Chicago, Illinois 60601. Inquiries from stockholders directed to the Board will be received and processed by the Corporate Secretary before being forwarded to the Board, the appropriate Committee or a particular director as designated in the communication.

Director Attendance at Our Annual Meeting and Board Meetings

While we do not have a formal policy regarding our directors' attendance at the Company's annual orand special meetings, our Board expects each director to attend, either in person or remotely via conference call, the Company's Annual Meeting of Stockholders each year, absent extenuating circumstances. EightAll of our nine directors serving on the Board in 20192020 at that time attended our 20192020 annual meeting. We currently anticipate that all our directors will attend the Annual Meeting, either in person or remotely.Meeting. During 2019,2020, each of our directors attended at least 75% of the meetings of the Board and Board committees on which they served.

Nominee Recommendations by Stockholders

Stockholders wishing to recommend persons for consideration by the Governance and Nominating Committee as nominees for election to the Board of Directors can do so by writing to the Governance and Nominating Committee at Byline Bancorp, Inc., Attention: Corporate Secretary, 180 North LaSalle Street, Suite 300, Chicago, Illinois 60601. Recommendations must include the proposed nominee's name, biographical data and qualifications as well as a written statement from the proposed nominee consenting to be named as a nominee and, if nominated and elected, to serve as a director. If all necessary information is provided, the Governance and Nominating Committee will then consider the candidate and the candidate's qualifications in the same manner as prospective nominees that are identified by the committee. The Governance and Nominating Committee may contact the stockholder making the nomination to discuss the qualifications of the candidate and the reasons for making the nomination.

Any stockholder seeking to nominate persons for election to our Board of Directors must comply with our procedures for stockholder nominations described under the heading "Stockholder Proposals."

Compensation Committee Interlocks and Insider Participation

None of the members of our Compensation Committee is currently or was previously an officer or employee of Byline or Byline Bank. In addition, none of our executive officers serves or has served as a member of the board of directors, compensation committee or other board committee performing equivalent functions of any company or other entity that has one or more executive officers serving as one of our directors or on our Compensation Committee.

Code of Business Conduct and Ethics

Our Board of Directors has adopted a code of business conduct and ethics (the "Code of Ethics") that applies to all of our directors, officers and employees, including our principal executive officer, principal financial officer and principal accounting officer and persons performing similar functions. Our Board has also adopted a Code of Ethics for Financial Officers. A copy of each code is available upon written request to Corporate Secretary, Byline Bancorp, Inc., 180 North LaSalle Street, Suite 300, Chicago, Illinois 60601 and on our website atwww.bylinebancorp.com under the "Governance Documents" tab. If we amend or grant any waiver from a provision of our Code of Ethics that applies to our executive officers, we will publicly disclose such amendment or waiver on our website and as required by applicable law, including by filing a Current Report on Form 8-K.

18    Byline Bancorp, Inc.  20202021 Proxy Statement

Table of Contents

Human Capital and Social Responsibility

We believe in being the bank our customers deserve, which, as embodied in our name, means taking ownership, initiative, action, and responsibility for what we do.

In order to achieve our vision to be the bank our customers deserve, we focus on:

•

Consistently delivering an extraordinary customer experience

•

Helping our customers bank the way they want to bank

•

Cultivating a positive culture and great place to work by finding, growing, and keeping talented employees

•

Contribute to the local communities in which we work and live to grow and thrive—today and into the future

To do this, we've outlined the Things That Matter (TTM) at Byline—values that guide our business, mission, and team culture:

Human Capital

Attracting, developing, and retaining the best people is crucial to our long-term strategy. Our business is about people—our customers and our employees. We seek to help our customers build, make, and do—none of which would be possible without our employees.

Byline Bancorp, Inc.  2021 Proxy Statement    19

Table of Contents

Employee Profile and Diversity

We embrace diversity within our teams and define diversity by both gender and people of color. Our key human capital diversity metrics are as follows:

* Diversity is defined by gender and people of color, as disclosed. Data as of December 31, 2020

Talent Attraction, Development and Retention

To facilitate talent attraction, development and retention across our franchise, we strive to make Byline a diverse, inclusive, safe and healthy workplace, with opportunities for our employees to grow and develop in their careers, supported by strong compensation, benefits, health and welfare programs. We believe the management and development of our employees is key to our strategic growth plan and longer-term succession planning. We seek to encourage and empower our team members to take initiative, make decisions, own their careers and build customers relationships through our programs and employee-led efforts and initiatives throughout Byline Bank.

We have developed initiatives that support physical, emotional, financial, and social wellbeing, including:

•

Competitive, performance-based compensation, including incentives tied to business and individual results

•

Comprehensive health and welfare benefits offerings

•

Savings and retirement planning resources through our 401(k) Plan and Employee Stock Purchase Plan

•

Access to employee assistance plans to help with financial planning and personal, family and life issues

We provide development opportunities to our employees. We recognize the critical importance of providing career development and advancement opportunities for all employees. Accordingly, we provide a variety of formal and informal development opportunities to help employees grow in their current roles and build new skills.

We encourage our team members to pursue educational opportunities that will help improve job performance and professional development. To further this goal, we reimburse tuition and certain fees for satisfactory completion of approved educational courses and certain certifications. In addition, we equip leaders with the tools to act as mentors and to give open and honest feedback and support, and we provide employees the resources and support to create and execute personalized developmental plans. Our Board of Directors oversees the succession planning for executive management on an annual basis.

20    Byline Bancorp, Inc.  2021 Proxy Statement

Table of Contents

Employee recognition and engagement is important for us. Some of the tools we have developed to achieve such a crucial objective are:

•

We conduct an annual employee engagement survey with over 90% participation.

•

We provide everyday recognition through our "Kudos Cards" that celebrate employees living our core values, or "Things That Matter".

•

Our annual CEO Circle Awards highlight our employees who have demonstrated extraordinary performance during the year and exemplify our values.

•

Our employee resource groups ("ERGs") were formed to facilitate equity and inclusion across the organization. These ERGs include: Women Empowered by Byline, LatinX, Black, Asian and LGBTQ+.

Diversity, Equity and Inclusion

At Byline, racism and discrimination in any form is not tolerated and we believe in supporting a culture of respect and inclusion. We commit to DEI as the foundation and catalyst for honoring our employees, engaging our customers and community, creating a great place to work, and ultimately driving business success.

We pledge to create an environment where every employee can bring their authentic self to work and know that their unique background, ethnicity, experiences, perspective, and contributions serve to strengthen us and where growth opportunities exist at all levels.

For our customers and community, we strive that you see through our actions that we value each of you and know we are better together. We move forward challenging ourselves to live this vision every day.

Our Board is fully committed to this purpose and in 2020 supported management in developing a comprehensive DEI Initiative. Lead by members of the executive team, a DEI Council was created with focus in four key areas:

Workforce — Promoting representation at all levels and in all areas and business lines of the bank, with attention on recruiting and developing diverse talent and focusing on engagement and employee recognition.

Workplace — Creating a culture where everyone brings their authentic self to work and knows that their unique background, ethnicity, experiences, perspective, and contribution serve to strengthen the bank and our culture.

Community — Building meaningful, productive relationships in the communities we work.

Marketplace — Providing our customers with products and services that meet their diverse needs, including support through digital strategies that align to the market.

Community Impact

We are proud to be a community bank. By supporting local businesses and working with families to protect and grow their money, we make our neighborhoods even stronger. That's what being in the community means to us. We are committed to helping the local communities in which we live and work to grow and thrive, today and into the future. One way we do this is by providing employees paid time off to participate in community-based volunteer programs. Throughout the year, employees make a positive impact in their local communities and have found a

Byline Bancorp, Inc.  2021 Proxy Statement    21

Table of Contents

multitude of special ways to continue volunteering during the pandemic. During 2020, Byline made and/or supported:

Director Compensation

The following table lists the individuals who served on our Board of Directors in 20192020 and the compensation received in 20192020 for their service as directors, other than with respect to Mr. Paracchini, our President, who during 2020 held the positions of President and Chief Executive Officer, whose compensation as an officer of the Company is detailed in the Summary Compensation Table in the "Executive Compensation" section of this Proxy Statement. All compensation paid to directors is for their service on both the Byline Board of Directors and the Byline Bank Board of Directors.

(1)

See "Byline Bancorp, Inc. Director Compensation Program" below for a description of Mr. Herencia's Compensation arrangements in his role during 2020 as Chairman of the Board. Mr. Cabrera received $15,000 for his service as Chair of the Byline Bank's Executive Credit Committee and $5,000 for his service as a member of the Audit Committee; Ms. Herseth received $2,917$5,000 for her service as a member of the Byline Bank's Executive Credit Committee for a portion of the year;Committee; Mr. Kistner received $10,000 for his service as Chair of the Audit Committee; Mr. Del Valle Perochena received $5,000 for his service as Chair of the Compensation Committee;Committee and $3,750 for his service as Chair of the Governance and Nominating Committee (for a portion of the year); Mr. Rull received $5,000 for his service as a member of the Audit Committee and $2,083 for his service as Chair of the Risk Committee (for a portion of the year);Committee; Mr. Ruiz SacristanKent received $5,000$1,250 for his service as a member of the Byline Bank's Executive Credit Committee and $5,000 for his service as Chair of the Governance and Nominating Committee;Committee.

(2)

Reflects payments made by the Bank for health, dental and vision insurance premiums and amounts paid for cell phone expenses for Mr. Herencia.

(3)

Ms. Herseth was appointed toJaime Ruiz Sacristán served as a Director until April 12, 2020, Mr. Ruiz Sacristan received $1,667 for his service as Chair of the Board on April 2, 2019,Governance and Nominating Committee and $1,666 for his service as a member of Byline Bank's Executive Credit Committee, ALCO Committee and Trust Committee on June 7, 2019; Mr. Kent was appointed to the Board on June 7, 2019.Committee.

(4)

See "Appointment"Retirement of Robert R. Yohanan tofrom Byline's and Byline Bank's Board of Directors".

22    Byline Bancorp, Inc.  2021 Proxy Statement

Table of Contents

Byline Bancorp, Inc. Director Compensation Program

Our director compensation program provides the following compensation for non-employee members of our Board of Directors:

•

An annual cash retainer of $100,000 for directors who were serving on June 1, 2016 and $75,000 for all other directors;

•

An additional annual cash retainer of $5,000 for the Chair of the Risk Committee;

•

An additional annual cash retainer of $10,000 for the Chair of the Audit Committee;

•

An additional annual cash retainer of $5,000 for the Chair of the Compensation Committee;

•

An additional annual cash retainer of $5,000 for the Chair of the Governance and Nominating Committee;

•

An additional annual membership fee of $5,000 for each member of the Audit Committee and/or the Bank's Executive Credit Committee; and

•

An additional annual cash retainer of $15,000 for the Chair of the Bank's Executive Credit Committee;

We also reimburse all directors for reasonable and substantiated out-of-pocket expenses incurred in connection with the performance of their duties as directors. Additionally, the Chairman of the Board is reimbursed forentitled to reimbursement of cell phone services and certain medical and health insurance expenses.

20    Byline Bancorp, Inc.  2020 Proxy Statement

Table of Contents

Directors agree, in connection with their service as directors, that they will not, without the prior consent of Byline, directly or indirectly, provide any material services to any other banking entity which competes in any material respect with Byline and its subsidiaries as long as they serve as a director of Byline (other than services disclosed in writing).

Notwithstanding the above, any director who is an officer of Byline will not receive any separate compensation for serving as a director of the Company or the BankBank.

Compensation PayablePaid to Mr. Herencia in 2020

Mr. Herencia is a founder of Byline, and his leadership was instrumental in the organization and recapitalization of our business in 2013. During that time, he organized the investor group, recruited the management team, and provided significant expertise resulting in the Company's financial and regulatory turnaround. Mr. Herencia played a leading role in two of the largest bank recapitalizations of troubled institutions during the Great Recession, including the $206 million recapitalization of the Company, and has specific expertise in raising capital and securing improvements in the governance and safety and soundness of community banks.

The Board considers Mr. Herencia to have specialized expertise which is applied to improve decision making and outcomes at the senior management and Board level. Mr. Herencia's extensive experience in the banking industry, substantial dealings with banking regulators, strong credit and lending background, as well as his turnaround and mergers and acquisitions expertise, continue to be vital as Byline executes on its strategy and addresses the current and unprecedented economic environment. He has extensive knowledge about our customers and competitors, as well as the complexities of regulatory compliance and the risk management environment.

As Chairman of the Board from 2013 until February 2021, Mr. Herencia's isHerencia has been involved heavily with Board matters and overseeing managementmanagement's execution of the Board's guidance. He actively interactsinteracted with the CEO and other members of management to provide his perspective on important issues facing our company and playsplayed an active role in the retention and recruiting of executive talent. It is the Board's position that his leadership is critical and his contributions in dealing with the effects of the COVID-19 pandemic will have long-term impact on the financial well-being of Byline.

Mr. Herencia's compensation for 2020 reflects his specialized expertise and the significant investment of time he spendsspent with the Board and executive leadership.leadership, especially in light of the unprecedented challenges our business and our customers faced as a result of the COVID-19 pandemic. As such, he receivesreceived an aggregate annual cash retainer of $400,000, which includesincluded the annual board retainer and all committee membership and committee chair retainers that the Chairman would otherwise be entitled to receive. Additionally, Mr. Herencia receivesreceived a payment of $400,000, payablepaid in two equal installments in March and September of each year2020 subject to continued service through such dates.

New Agreement with Mr. Herencia

In 2019,January of 2021, the Board evaluated certain proxy advisory analyses regardingconducted a deeper evaluation of Mr. Herencia's pay levels as Chairman. While these analyses were reviewed in 2019 and early 2020, the Board did not make a decision given the challenges that we may encounter due to the COVID-19 pandemic, where Mr. Herencia's specialized expertise may be needed and require him to further increase hissignificant ongoing involvement with management and his ability to have a substantial and positive impact on the Boardexecution of the Company's strategy. We announced the appointment of Mr. Herencia as Executive Chairman and senior management. It is anticipated thatChief Executive Officer of the Board will continue to evaluateByline, effective as of February 12, 2021, and entered into an employment agreement with Mr. Herencia's compensationHerencia in 2020 and will disclose any changes in accordanceconnection with applicable disclosure obligations.the assumption of his expanded role (the "Employment Agreement").

Byline Bancorp, Inc.  20202021 Proxy Statement    2123

Table of Contents

The Employment Agreement is for an initial term of three years and includes an automatic one-year extension at the end of each term following the initial term unless notice of termination is provided not less than 120 days prior to the end of such term. In addition, the Employment Agreement will terminate on the termination of Mr. Herencia's employment. Upon the occurrence of a Change in Control (as such term is defined in the Employment Agreement), the term of the Employment Agreement will renew for the period expiring on the second anniversary of such Change in Control and will automatically renew for one year on each subsequent anniversary of such date thereafter, unless at any time not less than 120 days prior to the end of such term either Byline or Mr. Herencia notifies the other in writing of the intention not to further extend the term.

During the term of the Employment Agreement, Mr. Herencia serves as Executive Chairman and Chief Executive Officer of the Byline, reporting to the Board, and Executive Chairman of the Board of Directors of the Bank. The Employment Agreement provides for an annual base salary of $825,000 (which may be increased but not decreased), eligibility to participate in (1) Byline's Executive Incentive Plan, with an annual target cash bonus of 75% of his annual base salary (or such other percentage as the Board may determine), and (2) Byline's long-term incentive awards annually under the 2017 Omnibus Incentive Compensation Plan (the "2017 Plan"), with an annual long-term incentive award target equal to 85% of his annual base salary. In connection with entering into the Employment Agreement, Mr. Herencia was awarded a restricted stock award of 109,475 shares of Byline's common stock under the 2017 Plan, vesting in equal installments at the end of 2021, 2022 and 2023.

The Employment Agreement also includes severance benefits that are subject to signing a release. If we terminate Mr. Herencia without "cause" (and not due to Disability (as such term is defined in the Employment Agreement) or Mr. Herencia resigns for "good reason" (provided that the expiration of the term of the Employment Agreement following the delivery by Byline of a notice of non-renewal of such term shall be deemed to be a termination of Mr. Herencia's employment by Byline without "cause"), other than on or following the occurrence of a Change in Control, he will be entitled to (each capitalized term as defined in the Employment Agreement): (1) the Accrued Amounts and any Unpaid EIP; (2) a Pro Rata Bonus; and (3) a cash amount equal to the sum of (a) the Severance Amount plus (b) the Applicable COBRA Amount, payable in substantially equal installments over 24 months following termination of employment. In the event Mr. Herencia is terminated without "cause" (and not due to Disability) or he resigns for "good reason" within two years following a Change in Control, he will be entitled to: (1) the Accrued Amounts and any Unpaid EIP; (2) a Pro Rata Bonus; and (3) a cash amount equal to the sum of (a) the CIC Severance Amount (as such term is defined in the Employment Agreement) plus (b) the Applicable COBRA Amount, payable in lump sum within 15 days after the release becomes effective.

"Cause" generally means: (1) a willful and continued failure to perform substantially one's duties; (2) willfully engaging in illegal conduct, an act of dishonesty or gross misconduct related to the performance of one's duties and responsibilities; (3) being charged with a crime involving moral turpitude, dishonesty, fraud, theft or financial impropriety; (4) willful violation of a material requirement of any applicable code of ethics or standards of conduct of Byline, or violation of a fiduciary duty to Byline; or (5) a breach of Byline's Agreement Protecting Company Interests.

"Good reason" generally means: (1) any material reduction in Mr. Herencia's base salary; (2) any material adverse change in Mr. Herencia's title, position, authority or reporting relationships, including, without limitation, ceasing to be the Executive Chairman and Chief Executive Officer of a publicly-traded company; (3) the requirement to relocate Mr. Herencia's principal place of employment to a location in excess of 50 miles from the his principal work location on the date of the Employment Agreement; or (4) the failure to nominate Mr. Herencia to, or his removal from, the Board of Directors of Byline or the Bank.

The Employment Agreement also provides that in the event his employment terminates due to death or Disability, Mr. Herencia or his estate would be entitled to receive, in addition to any accrued but unpaid compensation or benefits, any unpaid bonus earned with respect to any fiscal year ending on or preceding the date of termination and a pro rata portion of his bonus for the fiscal year in which the termination occurs, payable at the time that such bonuses are paid to other senior executives for such year. In addition, in the event of his death, Mr. Herencia's beneficiary would be entitled to a lump sum cash amount equal to $750,000.

As a condition to the Employment Agreement, Mr. Herencia has entered into an Agreement Protecting Company Interests with Byline, which contains (1) a confidentiality provision regarding the use and disclosure of confidential information during the term of employment and after, (2) a customer and employee non-solicit during employment and for 18 months following termination of employment, and (3) assignment of inventions and non-disparagement provisions.

24    Byline Bancorp, Inc.  2021 Proxy Statement

Table of Contents

	Proposal 2 Ratification of Independent Registered Public Accounting Firm Under its charter, the Audit Committee has the sole authority to appoint or replace our independent registered public accounting firm, subject to stockholder approval, and has direct responsibility for the compensation and oversight of such firm. Our independent registered public accounting firm for the fiscal year ended December 31, 20192020 was Moss Adams LLP ("Moss Adams") and the Audit Committee has engaged Moss Adams for the fiscal year ending December 31, 2020.2021.

The Board is submitting for ratification by our stockholders at the Annual Meeting the appointment of Moss Adams as our independent registered public accounting firm for the fiscal year ending December 31, 2020.2021. Moss Adams has served as our independent auditor since 2013. In considering the reappointment of Moss Adams for 2020,2021, the Audit Committee reviewed, among other considerations, the quality of services provided, both historically and onin connection with the most recent audit; Moss Adams' capability and expertise, particularly with respect to the financial services industry and its resources; the communication and interaction by Moss Adams' audit team with the Audit Committee and management; the firm's independence, objectivity and professional skepticism; and the appropriateness of Moss Adams' fees.

The Board has invited representatives of Moss Adams to be present at the Annual Meeting, and expects that they will attend. If present, these representatives will have the opportunity to make a statement if they desire to do so and are expected to be available to respond to appropriate questions from stockholders.

Fees Paid to Moss Adams LLP

The following is a summary and description of the aggregate fees for professional services provided by Moss Adams LLP to the CompanyByline and its subsidiaries for the fiscal years ended December 31, 20192020 and 2018,2019, as well as all out-of-pocket costs incurred in connection with these services that were billed to the Company.us.

Audit Fees.    Audit fees consist primarily of fees and expenses for the audits of the Company'sour annual consolidated financial statements as well as the review of interim condensed consolidated financial information included in the Company's reports we filed with the SEC. Also included are fees for services normally provided by an independent auditor in connection with statutory and regulatory filings.

Audit-Related Fees.    Audit-related fees consist primarily of fees related to the audit or review of our financial statements, including internal control reviews, as well as for the audit of the financial statements of our 401(k) plan.

Tax Fees.    Moss Adams LLP did not provide any tax services during 2019 or 2018.Plan.

22    Byline Bancorp, Inc.  20202021 Proxy Statement    25

Table of Contents

Audit Committee Preapproval Policies and Procedures

All of the fees and services described above under "audit fees," "audit-related fees," "tax fees" and "all other"audit-related fees" were pre-approved by the Audit Committee. Pursuant to the Audit Committeeits charter, the Audit Committee pre-approves all audit and permissible non-audit services provided by the independent public accounting firm. These services may include audit services, audit-related services, tax services and other services. In connection with the pre-approval of any permissible tax services or services related to internal control over financial reporting, the Audit Committee charter provides that the Audit Committee will discuss with the independent public accounting firm the potential impact on the firm's independence in providing such services. Any pre-approval is subject to receipt of details as to the service or category of services to be provided and the provision of supporting documentation at the time of approval. The Audit Committee may delegate pre-approval authority to one or more of its members. Such member must report any decisions to the Audit Committee at the next scheduled meeting.

THE BOARD OF DIRECTORS RECOMMENDS THAT YOU VOTE"FOR" THE RATIFICATION OF THE APPOINTMENT OF MOSS ADAMS LLP AS THE COMPANY'S INDEPENDENT REGISTERED PUBLIC ACCOUNTING FIRM FOR THE 20202021 FISCAL YEAR

26    Byline Bancorp, Inc.  20202021 Proxy Statement    23

Table of Contents

Report of the Audit Committee

The Audit Committee of the Board of Directors is responsible for providing independent, objective oversight of the Company's accounting functions and internal controls and is composed of directors that are "independent" as defined under the NYSE corporate governance listing standards and Rule 10A-3 of the Exchange Act. The Audit Committee operates under a written charter approved by the Board of Directors and held 1415 meetings during fiscal year 2019.2020. A copy of the charter is available on the Company'sour website atwww.bylinebancorp.com under the "Governance Documents" tab.

Management is responsible for the Company's internal control over financial reporting, disclosure controls and procedures and the financial reporting process. The independent registered public accounting firm is responsible for performing an independent audit of the Company'sour consolidated financial statements in accordance with Public Company Accounting Oversight Board (PCAOB) standards and to issue reports thereon. The Audit Committee's responsibility is to monitor and oversee these processes, including the activities of the Company's internal audit function. The Audit Committee has established a mechanism to receive, retain and process complaints on auditing, accounting and internal control issues, including the confidential, anonymous submission by employees and others of concerns on questionable accounting and auditing matters.

In connection with these responsibilities, the Audit Committee met with management and the independent registered public accounting firm to review and discuss the 20192020 audited consolidated financial statements. The Audit Committee also discussed with the independent registered public accounting firm the matters required by PCAOB Auditing Standard No. 1301, Communications with Audit Committees. In addition, the Audit Committee received the written disclosures and letter from the independent registered public accounting firm required by applicable requirements of the PCAOB regarding the independent accountant's communications with the Audit Committee concerning independence, and the Audit Committee has discussed with the independent registered public accounting firm its independence from the Company and its management.

Based upon the Audit Committee's discussions with management and the independent registered public accounting firm, and the Audit Committee's review of the representations of management and the independent registered public accounting firm, the Audit Committee recommended that the Board of Directors include the Company's 2019Byline's 2020 audited consolidated financial statements in the Company'sour Annual Report on Form 10-K for fiscal 20192020 filed with the SEC.

This report is submitted on behalf of the current members of the Audit Committee:

This report shall not be deemed to be incorporated by reference by any general statement incorporating by reference this Proxy Statement into any filing under the Securities Act of 1933, as amended, or the Securities Exchange Act of 1934, as amended, and shall not otherwise be deemed filed under such acts.

24    Byline Bancorp, Inc.  20202021 Proxy Statement    27

Table of Contents

Executive Officers

The name, age, position and office, and business experience during at least the past five years, of our current executive officers, other than Mr. Herencia and Mr. Paracchini, are set forth below.

Thomas Abraham (55)(56) has served as President of Byline'sByline Bank's Small Business Capital ("SBC") line of business since May 2019. Mr. Abraham was promoted to this position after having served as Senior Vice President, SBA Sales Manager of SBC since DecemberOctober 2016 when Byline Bancorp acquired SBC's predecessor company, Ridgestone Bank. Mr. Abraham served as Senior Vice President, Sales and Marketing at Ridgestone Bank from February 2007 through December 2016, where he helped build the government guaranteed lending framework for loan originations, credit processing and closing footprint, as well as sales generation, back-end operations and portfolio servicing. Earlier in his career, Mr. Abraham held business development and commercial lending positions at Popular Community Bank, QuesTech Financial Services, and Sanwa Business Credit. Mr. Abraham received a bachelor's degree from DePaul University.October 2016.

John M. Barkidjija (57)(58) has served as Executive Vice President and Head of Commercial Real Estate and Specialty Finance of Byline Bank since January 2019. Previously, Mr. Barkidjija was Senior Vice President, Group Head, Commercial Real Estate of Byline Bank since January 2014. Prior to joining Byline, Mr. Barkidjija served as a consultant and Chief Credit Officer at Bridgeview Bank, a Principal with Mbark Financial, LLC, Executive Vice President—Asset Management and Special Asset Consultant at ST Residential, LLC, Executive Vice President and Chief Credit Risk Officer at Corus Bank, N.A. Prior to his career in banking, Mr. Barkidjija also practiced corporate law at Christy & Viener and Jones & Blouch. Mr. Barkidjija received a B.A. in English literature from Columbia University's Columbia College, a J.D. degree from New York University School of Law and an M.B.A. with honors from the University of Chicago Booth School of Business.

Owen Beacom (61) has served as Chief Credit Officer of Byline Bancorp, Inc. and Byline Bank since August 2019. Mr. Beacom has more than 35 years of experience in the banking industry. He joined Byline following its acquisition of First Evanston Bancorp, where he served as Managing Director, Chief Lending Officer from 2004 to 2018. From 1990 to 2004, Mr. Beacom held senior lending positions at a number of Chicago area banks including Bank One, American National Bank of Chicago, and Lake Shore National Bank. Since 2012, Mr. Beacom has served as a member director of the Federal Home Loan Bank of Chicago. Mr. Beacom has a bachelor's degree in economics from Harvard University, a master's degree in accounting from DePaul University, and a master's degree in business administration from the University of Chicago.

Thomas J. Bell III (54) has been Senior Vice President and Corporate Treasurer of Byline Bank since August 2013. Prior to joining Byline, Mr. Bell served as a consultant for and then the Senior Vice President, Treasurer and Head of Planning of Anchor Bancorp from July 2010 to August 2013 where he was responsible for treasury, finance and capital management. Prior to joining Anchor Bancorp, Mr. Bell was an Executive Vice President, Treasurer and Chief Investment Officer for Midwest Banc Holdings, Inc. from December 2008 to June 2010. Prior to that experience, Mr. Bell served as a Senior Vice President with for ABN AMRO North America Inc., a Chicago-based holding company for the LaSalle Bank Corporation. Prior to his experience at ABM AMRO North America, Inc., Mr. Bell spent several years with the Federal Reserve Bank of Chicago. Mr. Bell received a bachelor's degree in finance from Lewis University.

Megan Biggam (41)(42) has served as Executive Vice President of Retail Banking of Byline Bank since February 2020. Ms. Biggam previously held the position of Senior Vice President of Retail Banking of Byline Bank since June 2013. Prior to joining Byline, Ms. Biggam was the Director of Marketing of Metrobank Group, Byline's predecessor bank parent, from August 2008 to June 2013. Prior to joining Metrobank Group, Ms. Biggam was a Division Marketing Manager at Washington Mutual, overseeing the retail marketing development for the Chicago, Atlanta and New Jersey markets. Prior to joining Washington Mutual, Ms. Biggam was the Regional Marketing Director for TCF Bank for the Chicago and Milwaukee markets. Ms. Biggam received a bachelor's degree in journalism from Indiana University.

Lindsay Corby (42)(43) has beenserved as Executive Vice President and Chief Financial Officer of Byline and Byline Bank since July 2015. Ms. Corby joined Byline in June 2013, serving as Chief Administrative Officer until July 2015. Prior to joining Byline, Ms. Corby was a Principal at BXM Holdings, Inc. from February 2011 to June 2013. In addition, Ms. Corby served on the board of directors of QCR Holdings, Inc., a public bank holding company, from 2012 to 2016. Since 2018, Ms. Corby has served on the board of directors of InnerWorkings, a marketing execution public

Byline Bancorp, Inc.  2020 Proxy Statement    25

Table of Contents

company. Prior to joining BXM Holdings, Inc., Ms. Corby was a Vice President in the investment banking group of Keefe, Bruyette & Woods, Inc., focused on mergers and acquisitions, capital markets transactions, complex recapitalizations and valuation activities for U.S. financial institutions. Ms. Corby received a bachelor's degree in Spanish, a bachelor of business administration in accounting and a master's degree in accounting from Southern Methodist University. Ms. Corby is also a registered Certified Public Accountant.

Donald J. Gibson Jr.Mark Fucinato (61)(64) has served as Executive Vice President and General Counsel ofChief Credit Officer for Byline Bancorp, Inc. and Byline Bank since June 2019. Mr. GibsonAugust 2020. He joined Byline fromBank in August 2019 as Senior Vice President and Senior Credit Officer. Prior to joining Byline, Mr. Fucinato served as Senior Credit Officer at MB Financial Bank N.A., where he served as General Counsel since 2014. Priorfrom 2016 to MB Financial2019, and at FirstMerit Bank Mr. Gibson was a partner at Chicago-based McGuireWoods, LLP, where he chaired the firm's community banking industry team. Before McGuireWoods, Mr. Gibson was a partner at Ross & Hardies, L.P., was a founding partner of Tatooles, Foley, Kluever & Gibson, and served as general counsel and assistant general counsel at Boulevard Bancorp, Inc. Mr. Gibson received his BA from Loyola University Chicago and a JD from Loyola University School of Law.2010 to 2016.

Michelle Johnson (39)(40) has served as Senior Vice President and Chief Risk Officer of Byline Bank since October 2019. Ms. Johnson joined Byline Bank in 2015, as the Director of Operational Risk Management and assumed the role of Deputy Chief Risk Officer in 2018. She

Nicolas Mando (49) has spentserved as Senior Vice President and Chief Technology and Operations Officer at Byline Bank since 2021. He joined Byline in 2019 as Director of Special Projects. Prior to joining Byline, he held the majority of her career in financial services, where she has held numerous roles including in the areas of enterprise risk, information security, and mergers and acquisitions. Ms. Johnson also served for ten years with the Army National Guard, as a Military PoliceChief Operating Officer and completed toursrole at Bridgeview Bank from 2009 to both Iraq and Afghanistan. She received a B.A. from Illinois State University, a M.S.from Norwich University, and is a Certified Information Systems Security Professional (CISSP) and Certified Enterprise Risk Professional (CERP).2019.

Brogan Ptacin (59)(60) has beenserved as an Executive Vice President and Head of Commercial Banking for Byline Bank since January 2019. Prior to joining Byline, Mr. Ptacin served as a Managing Director of First Bank & Trust from 2009 until First Bank & Trust was acquired by Byline in 2018. Previously, Mr. Ptacin2018, where he joined as Managing Director.

Dana Traci (51) has served as Executive Vice President and Chief Human Resources Officer of MidwestByline Bank & Trust, Executive Vice Presidentsince 2019. Prior to joining Byline, she was Interim Chief Human Resources Officer for Discover Financial Services, where she held a variety of Royal American Bank,business line and Senior Vice President of American National Bank & Trust. Mr. Ptacin received an BSBA in Finance from Creighton University.human resources roles since 1994.

Succession Planning

Our Board of Directors oversees both emergency and long-term succession planning for our Executive Chairman and CEO, President, CFO, and other key management roles within Byline. The succession plan is reviewed periodicallyannually to ensure a smooth transition in the event of a planned or unplanned vacancy in these positions. Succession planning for our executive officers other than the CEO is reviewed by the Board annually to identify potential successors and oversee their career development planning.

2628    Byline Bancorp, Inc.  20202021 Proxy Statement

Table of Contents

Executive Compensation

We are an "emerging growth company," as defined in the Jumpstart Our Business Startups Act of 2012, or the JOBS Act. As such, we are eligible to take advantage of certain exemptions from various reporting requirements that are applicable to other public companies that are not emerging growth companies. These include, but are not limited to, reduced disclosure obligations regarding executive compensation in our proxy statements, including the requirement to include a specific form of Compensation Discussion and Analysis, as well as exemptions from the requirement to hold a non-binding advisory vote on executive compensation. We have elected to comply with the scaled disclosure requirements applicable to emerging growth companies.

Introduction

The objective of our executive compensation program is to attract, retain, and motivate leaders who are committed to executing on our business strategy and creating long-term value for our stakeholders. To help us achieve these objectives, the Compensation Committee has designed an executive compensation program that consists of fixed and variable pay elements in the form of base salaries, annual cash and long-term equity incentives. The program is built on a foundation of best-in-class compensation governance practices and policies:

		We link a significant portion of compensation to performance using short-term (cash) and long-term (equity) compensation to encourage both proactivity and long-term sustainability.compensation.
		We employ a variety of performance metrics to deter excessive risk-taking by eliminating any incentive focus on a single performance goal.
		We have built in appropriate levels of discretion to adjust incentive payouts if results are not aligned with credit quality, regulatory compliance, or leading indicators of future financial results.
		We maintain stock ownership and retention guidelines for our executives and directors.
		We grant equity awards that have "double-trigger" equity vesting provisions upon a change in control.
		We do not provide significant perquisites.
		We engage an independent compensation consultant.
		We have a clawback policy.
		We prohibit hedging and pledging of our stock by our directors and executive officers.

Byline Bancorp, Inc.  20202021 Proxy Statement    2729

Table of Contents

In addition to the above, the table below summarizes what the Company does and does not do with respect to its compensation governance practices and demonstrates that the Company's practices are designed to encourage actions that are in the long-term interests of its stockholders.

What We Do		What We Don't Do
​	​	​
		​
Pay for Performance • We base our annual incentive compensation programs on the achievement of corporate and individual performance measures that are tied directly to our business strategy. • We link a significant portion of compensation to performance using short-term (cash) and long-term (equity) compensation to encourage both proactivity and long-term sustainability.compensation. Emphasize Long-term Performance • Equity programs reward performance over a three-year time horizon. Equity Awards • We grant equity awards that have "double-trigger" equity vesting provisions upon a change in control. Stock Ownership Commitment • Our stock ownership guideline policy ensures that our executive officers and directors own an appropriate amount of our common stock, which aligns their interests with our stockholders. Clawbacks • Our policy requires the recoupment of any excess incentive compensation paid to our executive officers if we are required to restate our financial statements due to material noncompliance with any financial reporting requirement under applicable securities laws. Risk Management • Our compensation plans are evaluated annually by our risk management professionals and our Compensation Committee, as part of its effort to ensure our compensation plans do not encourage imprudent risk taking. • We employ a variety of performance metrics to deter excessive risk-taking by elimination any incentive focus on a single performance goal. • We have built in appropriate levels of discretion to adjust incentive payouts if results are not aligned with credit quality, regulatory compliance, or leading indicators of future financial results. Compensation Benchmarking • We use a defined peer group for benchmarking, and the Compensation Committee periodically reviews the peer group to ensure the peer companies remain relevant and appropriate. Engage Independent Advisor • The Compensation Committee uses the services of an independent compensation consultant.		No Hedging or Pledging of Company Stock • We have a policy that prohibits all executive officers and directors from entering into any transaction designed to hedge or offset changes in the market value of our stock. The policy also prohibits holding our stock in a brokerage margin account or pledging our stock as collateral for a loan. No Extensive Use of Employment Agreements • We limit the use of employment agreements to our Executive Chairman and CEO, andPresident, CFO, and the President of our Small Business Capital business unit. No Significant Perquisites • We do not provide significant perquisites to our executive officers. No Golden Parachute Tax Gross-ups • We do not allow for tax gross-ups under employment agreements or other severance plans. No Multi-year Compensation Guarantees. • Our employment agreements and compensation plans generally do not provide for any multi-year compensation guarantees, other than the retention agreements with Messrs. Beacon and Ptacin entered into in connection with our acquisition of First Evanston Bancorp.guarantees. No Unearned Dividends Paid • We accrue dividends on performance-based restricted stock awards during performance periods, but the dividends are not paid until the award vests.

2830    Byline Bancorp, Inc.  20202021 Proxy Statement

Table of Contents

As we continue to grow, the Compensation Committee will review and adjust the design of the executive compensation program to ensure it remains aligned with our business objectives, talent strategy and market practices.

Summary Compensation Table

The named executive officers of Byline Bancorp, Inc. as of December 31, 2019,2020, are

•

Alberto J. Paracchini, President and Chief Executive Officer,

•

Lindsay Corby, Executive Vice President and Chief Financial Officer,

•

Owen Beacom, Executive ViceThomas Abraham, President and Chief Credit Officer,of Byline Small Business Capital, and

•

Brogan Ptacin, Executive Vice President and Head of Commercial Banking.

The following summary compensation table presents compensation awarded in the fiscal years ended December 31, 2017, 2018, 2019 and 20192020 to our named executive officers or paid to or accrued for those executive officers for services rendered during fiscal years 2017, 2018, 2019 and 2019,2020, as applicable. All share and option information in this section reflects our reincorporation from Illinois to Delaware in connection with our initial public offering in 2017, and the resulting exchange of one share of Byline Bancorp, Inc. Delaware common stock for every five shares of Byline Bancorp, Inc. Illinois common stock.

Byline Bancorp, Inc.  20202021 Proxy Statement    2931

Table of Contents

Narrative Disclosure to Summary Compensation Table

Base salary

Each named executive officer's base salary is a fixed component of compensation for each year for performing specific job duties and functions. The total base salaries earned by our named executive officers in fiscal years 2017, 2018, 2019 and 20192020 are disclosed in the Summary Compensation Table above.

Base salaries for our named executive officers are reviewed annually by the Compensation Committee. Mr.Messrs. Paracchini's, and Ms. Corby's and Mr. Abraham's base salary issalaries are established pursuant to their employment agreement with Byline Bank, as described under "Employment agreements with Mr. Paracchini, Ms. Corby and Ms. Corby"Mr. Abraham" below, but isare subject to review and approval of the Compensation Committee.

Annual incentive

Our named executive officers participate in Byline's Executive Incentive Plan, which was adopted by the Company in 2014 and is an annual incentive plan under which earned awards are determined following the end of each year based on corporate and individual achievement during the year. Results are assessed against performance goals and targets that are established for the fiscal year; for Mr. Paracchini and Ms. Corby, for each of 2017, 2018 and 2019, corporate goals were weighted 70% and individual performance goals were weighted 30%. Mr. Ptacin began participating in the Executive Incentive Plan in 2018 and Mr. Beacom began participating in 2019. For each of 2018 and 2019, namedyear, as described further below.

Named executive officers can earn up to a maximum of 150% of their target annual incentive awards and annual incentive awards may be as low as 0% if the Company's performance target is not met. The Compensation Committee has discretion to adjust awards in light of credit quality, regulatory compliance and financial result deemed relevant. Executives must be employed on the date of payment in order to receive payment of an earned award.

For 2019, theThe corporate scorecard measures included the following four categories of metrics: Profitability (40%), Loan Quality/Operational Soundness (30%); Expense Management and Profitability (20%) and Growth (10%).metrics. In addition, the Company must meet a threshold of equal to or greater than 90% of budgeted net income to trigger an award payout under the Executive Incentive Plan.

32    Byline Bancorp, Inc.  2021 Proxy Statement

Table of Contents

In 2019,2020, target annual cash incentives under the Executive Incentive Plan for each of our named executive officers were a percentage of the named executive officer's base salary. The following table presents each named executive officer's annual incentive opportunity, percentage of goal achievement and award payout under the Executive Incentive Plan.

Long-term incentive

The named executive officers participate in a Long-term Incentive Program ("LTIP") that provides a variable pay opportunity through a combination of performance shares and restricted shares. The program is designed to reinforce the long-term alignment of the Company's executives with the interests of our stockholders. Performance

30    Byline Bancorp, Inc.  2020 Proxy Statement

Table of Contents

shares are intended to strengthen our pay-for-performance philosophy while time-vested restricted shares are granted to promote share ownership and executive retention.

All awards under the LTIP are granted through the Byline Bancorp, Inc. 2017 Omnibus Incentive Compensation Plan. The following table presents each named executive officer's annual long-term incentive target:target for 2020:

•

Time-based Restricted Shares—50% of the shares are awarded with a service-based vesting schedule. Awards vest equally over three years on the anniversariesanniversary date of the grant date.grant. Awards vest automatically upon 1) death, 2) termination of employment due to disability and 3) termination upon the completion of a change-in-control.



•

Performance Shares—50% of the shares are awarded with performance-based vesting criteria. Vesting is dependent on the achievement of specified goals and is generally measured at the end of a three-year performance period ("Performance Period"). At the end of the Performance Period, the Compensation Committee will determine the level of goal attainment and determine the number of performance shares that actually vest.

Unless stated otherwise in the award agreement, upon 1) death, 2) termination of employment due to disability and 3) retirement, the Participant receives an award based on actual performance at the end of the Performance Period, prorated for the period of time in which the Participant was actively employed. Awards continue to vest upon a change-in-control if the successor entity assumes the existing awards. If a Participant is terminated within one year of the completion of a change-in-control, performance shares vest at target-level performance, without proration.

Byline Bancorp, Inc.  2021 Proxy Statement    33

Table of Contents

Similarly, if the successor entity does not assume the existing awards, the performance shares vest at target-level performance, without proration.

ReturnAverage return on assets (ROA), defined as net income as a percent of average assets, was approved by the Compensation Committee as the Corporate metric for the 2019—20212020—2022 LTIP. For this Performance Period, earned awards will vest at the end of the Performance Period, based on relative ROAaverage return on assets using an index of banks that arepublicly traded bank holding companies ranging in asset size from 50% to 200% the size of Byline.Byline's total assets. Performance will be measured cumulatively at the end of the Performance Period. Threshold, target and superior performance levels are set at the 25^th, 50^th and 75^th percentiles of the peer index, respectively.

Our named executive officers may earn 25% of their target opportunity for threshold-level performance and up to 125%100% of their target opportunity, (2019 goal) and up to 150% of their target opportunity (2019—2021 goal) for superior-level performance. Amounts between threshold and superior are interpolated to reward incremental achievement and no amounts are paid with respect to a particular performance metric if actual results are below threshold.

Adjustment to Compensation Metrics

The Board of Directors and the Compensation Committee are actively monitoring the effects of the COVID-19 pandemic on the economy, the equity trading markets (including, in particular, the value of equity securities of financial institutions) and our operations and future results. In light of these developments, the Compensation Committee will evaluate the actual and potential effects on our business results, financial condition and stockholder value. Performance goals and the incentives associated with our executive and management compensation and

Byline Bancorp, Inc.  2020 Proxy Statement    31

Table of Contents