Smith joins from WCRS, where he was a group account director with responsibility for COI, Mini and GlaxoSmith Kline.
Before his move, Smith was in the process of returning to his previous job at Lowe London, where he ran its Stella Artois account globally.
Smith's appointment sees him reunited with Euro RSCG's new managing partners Mark Cadman and Russ Lidstone, with whom he worked at Lowe.
Smith will focus on new business and marketing.
The move is the first in what is expected to be a series of planned senior appointments at Euro RSCG following Cadman and Lidstone's appointments in January.
Cadman said: "Mike comes to us with loads of experience and it is fantastic that he is joining us. We have worked well with him before, so it was an easy decision."
Smith added: "There's a great team, a desire to make good work and lots of opportunity at Euro RSCG. It's a natural fit for me."
Following Smith's appointment, Naomi Troni, the Euro RSCG new-business director, will move into the newly created position of client development director.
She has a brief to strengthen the group's new media and integrated offering. She will also retain her responsibility for running the agency's News Group account.