Store, 35, joins Starcom MediaVest from Profero. He joined the digital agency two years ago as its first client services director, and was instrumental in winning new business that included briefs from COI Communications, Disney and AstraZeneca.
Working from Starcom's London office, Store will work across the agency's multi-national clients in the region, with the network services team reporting directly to him.
Store spent 12 years at Carat, the last five as a Carat International group account director on flagship accounts including Adidas, Philips and Disney.
Gary Brown, Starcom MediaVest's chief operations director for Europe, the Middle East and Africa, said: "Eamonn's passion and ability to identify client media needs is exceptional. I know his skills are going to be immensely valuable."