Active as a double bassist until 1984, Karlheinz Essl played in chamber and experimental jazz ensembles. As a composer he has contributed to the Projekt 3 composition programming environment of Gottfried Michael Koenig at Utrecht and Arnheim (1988-89) which later transformed into his own Real Time Composition Library (RTC-lib) for Max/MSP/Jitter.
Essl also served as composer-in-residence at the Darmstadt summer courses (1990-94) and completed a commission for IRCAM. Between 1995-2006 he taught Algorithmic Composition at the Studio for Advanced Music & Media Technology at the Bruckner University, Linz. Professor of composition for electro-acoustic and experimental music at the Vienna University of Music and Performing Arts as of 2007.
Essl's compositions result from confrontations between ordered, abstract models and original tonal, expressive structures. He has frequently sought to combine music with other genres and has collaborated with the graffiti artist Harald Naegeli (Partikel-Bewegungen, 1991), the writer Andreas Okopenko and the artists' group Libraries of the Mind (Lexikon-Sonate, 1992--8), the architect Carmen Wiederin (Klanglabyrinth, 1992-95) and the video artist Vibeke Sorensen (MindShipMind, 1996, a multimedia installation for the Internet). During the 1990s he carried out many additional projects for the Internet and became increasingly involved with improvisation.
In 1997, Karlheinz Essl was featured at the Salzburg Festival with portrait concerts and sound installations. In 2003, he was artist-in-residence of the festival musik aktuell, and in 2004 he was presented with a series of portrait concerts at the Brucknerhaus Linz. In 2004, Karlheinz Essl received the cultural prize for music of the state Lower Austria. Besides writing instrumental music, Karlheinz Essl also works in the field of electronic music, interactive realtime compositions and sound installations. He develops software environments for algorithmic composition and acts as a performer and improviser.
Most of his compositions are published by TONOS (Darmstadt). Since 1992, he acts as the music curator of the Essl Collection in Klosterneuburg / Vienna.