Exhibit 23

Consent of Independent Registered Public Accounting Firm

The Board of Directors

First Business Financial Services, Inc.:

We consent to the incorporation by reference in Registration Statement Nos. 333-183274, 333-231418, 333-248131, and 333-256132 on Form S-8 of First Business Financial Services, Inc. of our report dated February 22, 2023 relating to the financial statements and effectiveness of internal control over financial reporting, appearing in this Annual Report on Form 10-K.

/s/ Crowe LLP

Oak Brook, Illinois

February 22, 2023