Ernst Ottensamer was born in Upper Austria in 1955 and studied the clarinet at the Vienna University for Music and Performing Arts. In 1979 he became a clarinettist in the Vienna State Opera Orchestra and the Vienna Philharmonic, where he has served as principal since 1983. In 1986 he started teaching at the Vienna University for Music, where, since 2000, he has been clarinet professor.
He has been active in establishing several chamber music ensembles, including the Vienna Virtuosi, the Vienna Wind Ensemble and the Vienna Soloists Trio, and has appeared in concert with the Alban Berg Quartet, Artis Quartet and Hugo Wolf Quartet, and with Sir Simon Rattle, Sir André Previn, Daniel Barenboim, Oleg Maisenberg, Rudolf Buchbinder, Stefan Vladar, Julian Rachlin, Mischa Maisky, Edita Gruberova, Angelika Kirchschlager and Juliane Banse.
He has appeared as a soloist with the Vienna Philharmonic, Vienna Chamber Orchestra, Budapest Philharmonic, Salzburg Mozart Orchestra, Linz Bruckner Orchestra, the Gächinger Kantorei and the Tokyo Philharmonic, under conductors including Hans Graf, Sándor Végh, Helmuth Rilling, Leopold Hager, Simone Young and Sir Colin Davis. He has made a number of recordings.