Wagner, who is 58, studied physics at the Technical University of Munich and the universities of Göttingen and Heidelberg. After spells as a research associate at Heidelberg and the Lawrence Berkeley Laboratory in California, Wagner became a full professor of experimental physics at Heidelberg in 1984. He accepted a chair at the University of Hamburg in 1991 and, in the same year, became director of research at DESY.

Wagner's research has centred on electron-positron collisions at DESY and at CERN. He was also closely involved in the preparation of the 1100-page conceptual-design report for TESLA, a superconducting 500 GeV electron-positron linear collider that he and Wiik hoped to build at DESY. The Hamburg laboratory is one of three particle physics centres hoping to host the next-generation linear collider. Wagner has sat on many scientific advisory committees in Germany and further afield, including Italy, Japan, Russia and the United States.