Since September 2005 Clemens Unterreiner has been a soloist and ensemble member at the Vienna State Opera where he could establish himself as one of the most popular and upcoming baritones. He sings Sharpless, Faninal, Angelotti, Schtschelkalow, Schaunard, Donner, Melot, Harlekin and works together with conducters like Franz Welser-Möst, Christian Thielemann, Simon Rattle, Philippe Jordan, Marco Armiliato, Peter Schneider, Andris Nelsons, Fabio Luisi, Asher Fisch, Yves Abel, Dennis Russell Davies, Ádam Fischer and others. In 2008 he sang Sharpless, Sprecher, Falke and Papageno as a guest solist at the Volksoper Wien.
Born and raised in Vienna, Clemens Unterreiner spent his childhood in Graz and Budapest. After he completed his school at the Academic High School he started studying Law at the University of Vienna. During his studies, he began to train his voice and to deepen his knowledge in music theory. In 1998 he started singing lessons with Prof. KS. Hilde Rössel-Majdan, Prof. KS. Gottfried Hornik, Prof. Helena Lazarska and KS. Wicus Slabbert (KS = singer of outstanding merit, in German "Kammersänger"). He also participated in master classes with Prof. KS. Bernd Weikl, KS. Artur Korn and Prof. KS. Gottfried Hornik. In 2000 he was awarded a Bayreuth Festival Scholarship and in 2002 he was a semifinalist at the International Belvedere Singing Competition in Vienna. His extensive repertory includes lyric italian, german and french chivalrous and heroic baritone parts, operetta as well as a wide range of art songs (Schubert, Schumann, Strauss, Brahms, Wolf), but also contemporary works of various composers.
He started his carreer at the annual Vienna Festival (Wiener Festwochen) and performed in Bulgaria, Syria, Italy, Spain and Germany. He performed at the Grand Hall of the Wiener Musikverein, at the Vienna Concert House (Wiener Konzerthaus), Palao de la Musica Barcelona and other international concert halls. He sang concert performances of "La Traviata" - Germont, "Fidelio" - Pizarro, "Tosca" - Scarpia and in October 2002 he made his opera debut at the State Theatre in Linz for the European premiere of "The Voyage" by Philip Glass. During the summer of 2003 he sang Count Baccellone in "La Contessina". Further engagements took him to the Vienna State Opera where he performed (2004) the premiere of Massenet’s "Werther". He sang Sharpless in "Madama Butterfly" in Chur, Strasbourg and Großes Festspielhaus Salzburg which was awarded the Prize of the Music Theatre 2004 season. During the summer of 2005 he sang the leading role in "Don Giovanni" at the Heidenheim Opera Festival in Germany and Bartolo in Paisiello's "Il barbiere di Siviglia". On September 4th 2005 he had his house debut in Puccini's "Manon Lescaut" where he started his carreer as a soloist and ensemble member of the Vienna State Opera. In 2006 he sang Hermann, Schlemihl and Crespél in "The Tales of Hoffmann" and Don Parmenione in Rossini's "L'occasione fa il ladro". 2007 he was heard as Don Fernando - Minister in "Fidelio" and celebrated with great success his debut as Guglielmo in "Così fan tutte". In 2008 he was guest soloist at the Opera Festival of Steyr, where he gained popularity as Consul Sharpless in Puccini's "Madama Butterfly". Following his celebrated performance in Upper Austria, he debuted in fall 2008 in his starring role as Consul Sharpless (Italian original version) at the Vienna Volksoper. The part of Papageno wasn't less suitable for his outstanding talent in 2009. In the same year he made his debut as feted Sulpice, when "La fille du régiment" finally premiered. In 2010 he celebrated as Donner a successful home debut in "Rheingold" at the Wagner-Festival Budapest and sang 2011 at the Royal Opera Copenhagen Sharpless (Madama Butterfly). In 2012, he sang Melot at the Opera House in Nice and debuted at the Salzburg Festival and in the new production of the Vienna State Opera, Gluck's Alceste as high priest/god of the underworld. 2013 he celebrated a brilliant success as Papageno in Mozart's "Die Zauberflöte" at the Opera de Nice and a highly acclaimed Wolfram in Wagner's Tannhäuser. He sang at the State Opera in the new production of Puccinis "La Fanciulla del West" and celebrated as Mayor considerable success in the world premiere of the childrens opera "Das Städchen Drumherum".