Richards takes up the newly created role next week. "My brief is to improve both the quality of the output and the staff as well as growing the relationship with Omnicom," he said.
He joins the Omnicom-owned company a year after resigning from Grey without a job to go to. Since then, he has been working as a freelance consultant.
Richards quit Grey in March last year amid a major restructuring of the agency's senior management by its then chief executive, Garry Lace.
Richards joined Grey in April 1997 and took charge of its flagship Procter & Gamble and Mars accounts.
"I have had no wish to return to a mainstream agency," he said. "I find the attitude of that environment somewhere between a dinosaur and an ostrich. There's lots of talk about brand consultancy but few do it well."