Schager sang lyrical tenor parts as a guest in Bologna, at the Oper Frankfurt, in Ghent and in Vienna, and at the Canadian Opera Company,[1] including Tamino in Mozart's Die Zauberflöte.

[2] He appeared as Tristan first at the Stadttheater Minden in 2012, alongside Dara Hobbs as Isolde, with the Nordwestdeutsche Philharmonie conducted by Frank Beermann directed by Matthias von Stegmann.

[3] The performance was noticed internationally; reviewers noted the singers' intensity and authenticity, and described Schager's Tristan as a "boisterous, passionate firebrand and dare-devil, whose ego does not have space for self-doubt.

She described him as a truly intelligent actor who is capable of great nuances ("... und daneben ein wirklich intelligenter Darsteller, der zu großartigen Nuancierungen fähig ist").

[12] Anthony Tommasini, a music critic at The New York Times, wrote: "Mr. Schager pretty much met expectations, which is saying a lot given the paucity of tenors who can sing Siegfried.

He was the tenor soloist in Mahler's Das Lied von der Erde at the Südtiroler Festspiele in Toblach and in Hamburg with choir and orchestra of the NDR,[1] and in Beethoven's Ninth Symphony in Bolzano and Ravenna.