CrossFirst Bankshares (CFB) 10-Q 2023 Q3 Quarterly report

Exhibit 32.1

CERTIFICATION OF PRINCIPALEXECUTIVE OFFICER AND PRINCIPALFINANCIAL OFFICER

UNDER 18 U.S.C. § 1350 FURNISHED PURSUANT TO SECURITIES EXCHANGEACT RULE 13a-14(b)

In connection with the Quarterly Report of CrossFirst Bankshares, Inc. (the “Company”)on Form 10-Q for the period ended on

September 30, 2023, as filed with the Securities and Exchange Commission on the datehereof (the “Report”), each of the undersigned, in

his respective capacities indicated below, hereby certifies, pursuant to 18 U.S.C.§ 1350, as enacted by Section 906 of the Sarbanes-Oxley

Act of 2002, that, to his knowledge and belief, (1) the Report fully complies with the requirementsof Section 13(a) or 15(d) of the

Securities Exchange Act of 1934, as amended, and (2) the information contained in the Report fairly presents, in all material respects,the

financial condition and results of operations of the Company.

Date: November 3, 2023

/s/ Michael J. Maddox

Michael J. Maddox

President and Chief Executive Officer (Principal Executive Officer)

/s/ Benjamin R. Clouse

Benjamin R. Clouse

Chief Financial Officer (Principal Financial Officer)