Before entering the NASCAR industry, Newmark was a shareholder at the law firm of Robinson, Bradshaw and Hinson. In his tenure with the company, Newmark not only represented teams, drivers, and sponsors, but also represented Ray Evernham and related companies in the sale of Evernham Motorsports to George Gillett.

Since 2010, Steve Newmark has an integral part of RFK Racing in the NASCAR Cup Series. He led the Jack Roush-owned team through its downsizing, as well as later restructuring and rebuilding under Brad Keselowski. The team currently runs three full-time teams with Keselowski in the No. 6, Chris Buescher in the No. 17, and Ryan Preece in the No. 60.