Theophilakis, a former creative head of Bates Europe, will have a roving role across all six of S&J's European offices. This will include working with Boy Meets Girl S&J, the rebranded London office that was launched in partnership with Interpublic Group, the St Luke's founding partner Andy Law, the former St Luke's deputy chairman, Kate Stanners, and David Pemsel earlier this month.
Oliver Schwall, Springer & Jacoby's managing director of international networks, said: "Aris' international experience and creative track record make him the ideal partner to develop our creative product across several countries and cultures. We are pleased to have him on board."
Theophilakis, a Cannes gold Lion winner, has developed international campaigns for clients including Audi, Nokia, Heineken and HSBC. He has also held the post of regional creative director for Bates Asia, based in Singapore.
The appointment is part of S&J's long-term aim of building its presence outside its strongest market, Germany. It plans to move its international headquarters to Amsterdam within the next month.
"S&J is the third alternative in a world of mega-networks and standalone boutiques," Theophilakis said. "With its strong European heritage and focus on great ideas, clients will be able to get more relevant thinking and better resources in a more nimble package."
S&J London was relaunched in an attempt to revitalise the agency, which has failed to make a mark since opening its doors in 1999.
S&J, which employs 560 staff, has major clients including the car manufacturer DaimlerChrysler, which owns the Mercedes-Benz and Smart car brands, Unilever and Coca-Cola.