Edwards joins Manning Gottlieb as the head of client service and will form part of an eight-strong board at the agency, headed by the managing director, Robert Ffitch.
Edwards' main role is to head MG OMD's eight account teams and to be responsible for relationships across the agency's 82 clients. In addition, he will work on general management projects and on developing the future of the business.
At MediaCom, Edwards currently runs the Volkswagen and Churchill accounts. He was promoted to the agency's board in January 2004.
Ffitch said: "It has taken eight months to find the right person to fill this role and we are delighted to have persuaded Steve to join us. His personality will fit in perfectly, his ambition will drive us and his ability will improve us."
MG OMD's other board members are Phil Nunn, the head of business development, Jon Gittings, the head of strategic planning, Stephen Hall, the head of INvents, Amy Lennox, the head of digital, Mark Gallagher, the head of press, and Bijan White, the head of broadcast.