Following his studies at the University for Music in Vienna, Andreas Schager started his career singing operetta and lyrical roles in the operas by Mozart before switching to the Helden roles in the works by Wagner and Strauss. In summer 2009, he made his highly regarded debut at the Tiroler Festspiele Erl as David in Die Meistersinger von Nürnberg, followed by engagements as Florestan/Fidelio, Max/Der Freischütz, Rienzi, Tristan, and Siegfried in both Götterdämmerung and Siegfried at small and middle-sized houses. His appearances as Siegfried/Götterdämmerung at the Staatsoper Unter den Linden Berlin, at the BBC Proms 2013 in London and the Teatro alla Scala, each under the baton of Daniel Barenboim resulted in his international breakthrough.

Andreas Schager has now established himself as one of the leading heroic tenors and sings at major venues and festivals worldwide, including the Metropolitan Opera, Opéra de Bastille, Vienna State Opera, Bavarian State Opera in Munich, Staatsoper Unter den Linden in Berlin, Deutsche Oper Berlin, Hamburg State Opera, Teatro alla Scala, Teatro Real Madrid, the opera houses in Frankfurt, Leipzig and Wiesbaden, as well as the Bayreuth Festival, and with conductors such as Philippe Jordan, Daniel Barenboim, Christian Thielemann, Valery Gergiev, Simone Young, Daniele Gatti, Franz Welser-Möst and Riccardo Chailly.

Operatic highlights of recent seasons include the Emperor in Die Frau ohne Schatten under Constantin Trinks at the Staatsoper Unter den Linden in Berlin, as well as Fidelio, Tristan und Isolde, Parsifal, Siegfried, Götterdämmerung and Ariadne auf Naxos, all conducted by Daniel Barenboim, Götterdämmerung at the Semperoper in Dresden under Christian Thielemann, Die Liebe der Danae at the Bavarian State Opera, Tannhäuser at the Deutsche Oper Berlin, Otello at the Staatstheater Wiesbaden and at the Vienna State Opera, where he also took on the roles of the Emperor/Die Frau ohne Schatten under Christian Thielemann, Tamino/Die Zauberflöte, the title role in Tristan und Isolde under Philippe Jordan, Apollo/Daphne and Lohengrin, both under Simone Young, Max/Der Freischütz under Tomá? Netopil and Siegmund and Siegfried in performances of Der Ring under Philippe Jordan. He also performed Parsifal and Tristan at the Opéra Bastille, Siegfried in Der Ring at the Hamburg State Opera under Kent Nagano and Siegfried and Götterdämmerung at the Metropolitan Opera in New York under Philippe Jordan and Tannhäuser under Donald Runnicles.

Andreas Schager is a welcome guest at the Bayreuth Festival, where he has made a name for himself as a heroic tenor in Wagner's great operas. Particularly noteworthy are his powerful performances as Siegfried in Der Ring des Nibelungen and Tristan in Tristan und Isolde, which have made him one of the most sought-after interpreters of these roles.

In addition to his outstanding opera successes, Andreas Schager is also active in the concert field. Highlights of recent years include performances with Franz Welser-Möst in Cleveland, Carnegie Hall and the New Year's Eve concert at the Semperoper in Dresden, Gurrelieder at the Philharmonie de Paris and Beethoven's Symphony No. 9 at the Wiener Konzerthaus with the Vienna Philharmonic, both under Philippe Jordan, Das Lied von der Erde under Valery Gergiev at the Philharmonie am Gasteig and the Elbphilharmonie, Mahler's Symphony No. 8 in Washington and under Riccardo Chailly in Lucerne, as well as Mahler's 'Symphony of a Thousand' with the Boston Symphony Orchestra conducted by Andris Nelsons and Beethoven's Symphony No. 9 with Marek Janowski and the Berlin Radio Symphony Orchestra.

Engagements of the 2025/26 season include the role of Siegfried in Götterdämmerung and Siegfried at Opéra National de Paris, the Royal Opera House London, the Berlin State Opera, and the Vienna State Opera, bringing the season to an end with the role of Rienzi in Parsifal at the Bayreuther Festspiele 2026.

In June 2025 Andreas Schager has been awarded the honorary title of ' Austrian Kammersänger'.