First Midwest Bancorp (ONBPP) S-4/A Registration of securities issued in business combination transactions (amended)

Exhibit 23.2

Consent of Independent Registered Public Accounting Firm

We consent to the reference to our firm under the caption “Experts” in Amendment No. 1 to the Registration Statement on Form S-4 and related Prospectus of First Midwest Bancorp, Inc. (the “Company”) and Proxy Statement of NI Bancshares Corporation for the registration of shares of First Midwest Bancorp, Inc.’s common stock and to the incorporation by reference therein of our reports dated March 2, 2015, with respect to the consolidated financial statements of the Company, and the effectiveness of internal control over financial reporting of the Company, included in its Annual Report (Form 10-K) for the year ended December 31, 2014, filed with the Securities and Exchange Commission.

/s/ Ernst & Young LLP

Chicago, Illinois

January 15, 2016