He will run the creative department and partner Stone Roberts, the chief executive, in heading new business.
In 1989, Langer was named as the chief executive of Lowe Partners/SMS, and, in January 1995, he moved to Lowe & Partners Worldwide as the vice-chairman.
Roberts said: "Andy and I have worked together off and on for more than 30 years. His work has brought tremendous style and creativity to his clients' brands. He will be a great partner as we move the agency forward together."