[1] List first began singing as a boy soprano in a Vienna choir, and also sang in the musical theater there.
In 1920, he returned to Vienna for additional training; his first opera role was at the Volksoper in 1922, as Mephistopheles in Charles Gounod's Faust.
That year he debuted in the role of Pogner in Wagner's Die Meistersinger, and went on to portray King Mark in Tristan und Isolde, Hunding in Die Walküre and Hagen in Götterdammerung, as well as Ramfis in Giuseppe Verdi's Aida and Baron Ochs in Richard Strauss's Der Rosenkavalier.
At the Salzburg Festival in Austria, List reprised his performance as King Mark and also played the roles of Osmin in Mozart's Die Entführung aus dem Serail and Commendatore in Don Giovanni, as well as Rocco in Beethoven's Fidelio.
List's Jewish heritage led him to leave Germany in 1933 for America; later that year he played the Landgrave in Wagner's Tannhäuser at the Metropolitan Opera, and remained in the company until 1950.