Hager studied piano, organ, harpsichord, conducting, and composition at the Salzburg Mozarteum (1949–1957) with Bernhard Paumgartner, Gerhard Wimberger, Cesar Bresgen, J.N. David, and Egon Kornauth. He was appointed assistant conductor at the Stadttheater Mainz (1957–1962) and, after conducting the Linz Landestheater (1962–1964), he was appointed first conductor of the Cologne Opera (1964–1965). He then served as Generalmusikdirektor in Freiburg im Breisgau (1965–1969), chief conductor of the Mozarteum Orchestra and of the Landestheater in Salzburg (1969–1981). In October 1976 he debuted at the Metropolitan Opera in New York, conducting Le nozze di Figaro. He also appeared as a guest conductor with other opera houses as well as orchestras in Europe (Berlin Philharmonic, Vienna Philharmonic) and the United States. In 1981, he became music director of the Orchestre Symphonique de Radio-Télé-Luxembourg (now the Luxembourg Philharmonic Orchestra), and concluded his tenure there in 1996.
Until 2004, Hager taught Orchestral Conducting at University of Music and Performing Arts, Vienna, continuing a direct line of renowned teachers including Clemens Krauss, Hans Swarowsky, and succeeding Österreicher.
From 2005 to 2008, Leopold Hager served as Chief Conductor at the Vienna Volksoper, conducting their new productions of The Magic Flute, La Traviata, Die Meistersinger von Nürnberg, Les Contes d'Hoffman and Turandot.
A frequent conductor at the Vienna State Opera, Leopold Hager has worked with such orchestras as the Vienna Philharmonic, Vienna Symphony, Czech Philharmonic Orchestra, Gewandhausorchester Leipzig, Staatskapelle Dresden, Munich Philharmonic, Münchner Rundfunkorchester, Bamberger Symphoniker, North German Radio Symphony Orchestra, MDR Leipzig Radio Symphony Orchestra, Berlin Symphony Orchestra, Royal Concertgebouw Orchestra, Accademia di Santa Cecilia, Danish National Radio Symphony Orchestra, Orchestre de Paris, Orchestre national de Lille and the National Symphony Orchestra in Washington, D.C.
| Music Director, Mozarteum Orchestra of Salzburg
Louis de Froment
| Music Director, RTL Grand Symphony Orchestra