EXHIBIT 31.1

Certification of Chief Executive Officer
Pursuant to Rules 13a-14(a) and 15d-14(a) of the Securities Exchange Act of 1934
and Section 302 of the Sarbanes-Oxley Act of 2002

I, Alberto J. Paracchini, certify that:

1.I have reviewed this Annual Report on Form 10-K/A (the “Report”) of Byline Bancorp, Inc. (the “Registrant”); and

2.Based on my knowledge, this Report does not contain any untrue statement of a material  fact or omit to state a material fact necessary to make the statements made, in light of the circumstances under which such statements were made, not misleading with respect to the period covered by this Report.