In the new role as head of activation, Adams will manage the digital activity for MEC's global clients, which include Sony Ericsson, Novartis and Paramount.
He will lead a 35-strong team of communications specialists working across 84 countries.
He joins MEC from Trade Doubler, where he led the international division and was responsible for new business revenue across 18 European markets.
Prior to that Adams was part of a management team at Yahoo! UK & Ireland, specialising in behavioural targeting, mobile, performance and graphical platforms.
He reports to Caroline Foster-Kenny, chief client officer for EMEA who said he joins as the agency aims to deliver a "new integrated, digitally-centric vision".
Last month, MEC appointed Ian Redman as business development director for Europe, Middle East and Africa, responsible for leading the pursuit of multi-market business in the EMEA region.