DMI traces its roots back to the J.L. Healy Construction Company, which incorporated in South Dakota in 1932. For 57 years the company concentrated on Highway Construction, and Utility work within the Midwest. In 1982, Pat Healy, J.L's son and CEO of the company, formed the Equipment Distributorship now known as Diesel Machinery, Inc. (DMI). The construction company was sold in 1989 as development of the equipment distributorship advanced.

Dan Healy, Pat's son now directs the operations of DMI as President. Dan started with the company in 1989 and has held various positions of increasing responsibility. With the help of Dan Rude (G.M.) and many other long term employees, DMI continues to stay focused on achieving its mission.