MillerKnoll (MLKN) 11-K Annual report of employee stock purchases

Exhibit 23(a)

Consent of Independent Registered Public Accounting Firm

To the Investment Committee of the

Herman Miller, Inc. Profit Sharing and 401(k) Plan

Zeeland, Michigan

We hereby consent to the incorporation by reference in the Registration Statement on Form

S-8 (002-84202) of Herman Miller, Inc. of our report dated June 27, 2018, relating to the financial statements and supplemental schedules of Herman Miller, Inc. Profit Sharing and 401(k) Plan which appear in this Form 11-K for the year ended December 31, 2017.

/s/ BDO USA, LLP

BDO USA, LLP

Grand Rapids, Michigan

June 27, 2018