Having notched up six years in operation, Creston is now planning to mirror its current UK offering in the US, covering advertising, PR, digital marketing, market research and direct marketing.
Elgie said: "In six years, we have succeeded in creating a high-value group delivering impressive earnings and growth on the London Stock Exchange. With nearly 900 employees in the UK, Creston is now positioned to achieve similar success in the US market."
Blamer said Creston's move would provide US agency entrepreneurs with an alternative to selling to the large holding companies.
He said: "Creston with its alternative model can provide the infrastructure and resources required to be nimble and entrepreneurial."
Blamer left Interpublic-owned FCB in June last year after it was announced it would merge with Interpublic's below-the-line network Draft to form DraftFCB. He was formerly the US CEO of ad agency network Grey, for which he worked for 17years.
Creston's revenues have grown by 49% year on year in the first half of its current financial year.
The group's major acquisition include ad agency DLKW in 2005, and market research group ICM and direct marketing agency Tullo Marshall Warren in 2006.