His brilliant performances in an early European tour led to his selection by the great conductor Otto Klemperer to perform the complete Beethoven Concerti at the London Beethoven Festival.
Apart from straight theatre, Gründgens also worked with Otto Klemperer at the Kroll Opera, as a Kabarett artist and also as a movie actor, most notably in Fritz Lang's 1931 film M, which decisively added to his popularity.
Otto von Bismarck | Otto | Otto III | Otto Piene | Otto I, Holy Roman Emperor | Otto I | Otto Preminger | Otto II | Otto Dix | Otto Natzler | Otto II, Holy Roman Emperor | Otto Binder | Otto Skorzeny | Otto Schenk | Otto of Brunswick | Otto Kerner, Jr. | Otto Steinbrinck | Otto Kerner | Otto IV, Holy Roman Emperor | Otto IV | Otto III, Holy Roman Emperor | Otto Braun | Miranda Otto | Frei Otto | Otto-Werner Mueller | Otto Schmidt | Otto Muehl | Otto Lilienthal | Otto Klemperer | Otto Hermann Kahn |
Outstanding among its conductors were Michael Taube, Georg Singer, Otto Klemperer, Heinz Freudenthal, Shalom Ronly-Riklis, Mendi Rodan, Lawrence Foster, Yoav Talmi, Sergiu Comissiona, Lukas Foss, Gary Bertini and David Shallon.
Before long, she was performing all over Europe and America, sharing the stage with such notable composers, conductors and singers as Edvard Grieg, Richard Strauss, Camille Saint-Saëns, Enrico Caruso, Otto Klemperer, Willem Mengelberg, Pablo Casals, Percy Grainger, Enrique Granados and Thomas Beecham.
He was the author of Conversations with Klemperer (1973) and Otto Klemperer: His Life and Times (2 vols, 1983-1996; 2nd vol completed by John Lucas).