His repertoire ranges from Baroque to the 21st century and includes approximately 100 roles from opera, operetta, oratorio and musical theatre. He has appeared in Mozart's operas as Don Giovanni, Papageno, Leporello, Guglielmo and Count Almaviva, in Puccini's La Boheme (Marcello and Schaunard) and Madame Butterfly (Sharpless), Wagner's Tannhäuser (Wolfram von Eschenbach), Parsifal (Amfortas), Tristan und Isolde (Kurwenal) and Die Meistersinger von Nürnberg (Beckmesser), Strauss' Elektra (Orest) and Ariadne auf Naxos (Harlekin), and has worked with directors such as Brigitte Fassbaender, Harry Kupfer, Sir David Pountney, Bob Wilson, Olivier Tambosi and La Fura dels Baus.
In 2009, Martin Achrainer sang the title role in the world premiere of the opera Kepler by Oscar-nominated composer Philip Glass. He has received further dedications and commissions from composers Rudolf Kelterborn, Kurt Schwertsik, Alexander Balanescu, Ernst Ludwig Leitner and Ingo Ingensand.

In addition to opera productions, he devotes himself to an extensive international
concert career, which has taken him to the Bregenz Festival, the Salzburg Festival, the
International Handel Festival in Göttingen and to major concert halls such as the Bunka Kaikan and Suntory Hall in Tokyo, the Festival Hall in Osaka, the Neue Oper Wien and the KKL Luzern, among others.

Martin Achrainer is a prize winner of the Robert Schumann Competition, the Hugo Wolf Prize Vienna, the ‘Gradus ad Parnassum’ and the International Hilde Zadek Singing Competition.
He has sung under renowned conductors such as Dennis Russell Davies, Kurt Masur, Marc Minkowski,
Markus Poschner, James Gaffigan, Franz Welser-Möst and Ralf Weikert, and has accepted invitations from the Latvian National Philharmonic Orchestra, the Vienna Radio Symphony Orchestra, the Lucerne Symphony Orchestra, the Basel Symphony Orchestra, the Theater an der Wien, the Brooklyn Academy of Music in New York, the Harris Theater in Chicago and many more.
Numerous international CD and DVD productions with works by Philip Glass, Franz Schubert, Franz von Suppé, Hugo Wolf and others, as well as radio and television recordings, document the versatility of his musical work.

Since 2015, Martin Achrainer has been teaching singing and vocal practice at the Institute for Music Education at the Bruckner University in Linz.