Kleinschuster was born in
Graz, and learned to play piano before learning how to play the trombone; his first major engagement was as a member of
Fridl Althaler's
Radio Graz dance orchestra. As a member of the
International Youth Band, he appeared at the 1958
Newport Jazz Festival, and worked with
Johannes Fehring from 1958 to 1965, in addition to playing with
Kenny Clarke and
Francy Boland's ensemble. He played with
Friedrich Gulda in 1965, then put together a six-piece ensemble the following year, which performed frequently on
Österreichischer Rundfunk. He founded Vienna's
Jazzinstitut in 1968 and was the leader of Österreichischer Rundfunk's big band from 1972 until 1981; he was the conductor for the Austrian entries of the
Eurovision Song Contest in 1972 and 1976. Among his jazz associations in the 1970s were
Stan Getz,
Astrud Gilberto,
George Gruntz,
Peter Herbolzheimer,
Gerry Mulligan, and
Toots Thielemans. In 1981 he moved back to Graz and became a lecturer in music at the Hochschule für Musik und Darstellende Kunst, a position he held until 1998; he also put together a youth orchestra, JAM, which toured in the early 1990s. ==References==