Michael Mantler was born in 1943 in Vienna, Austria, where he studied trumpet and musicology at the Academy of Music and Vienna University. In 1962 he went to the USA to continue his studies at the Berklee School of Music in Boston.
He moved to New York in 1964 and started playing trumpet with Cecil Taylor and others. During that period he was also involved in the formation of the Jazz Composer's Guild, a collective of musicians and composers, struggling for better working conditions and opportunities to present their new music without compromise. Together with Carla Bley he formed a large jazz orchestra to perform new compositions, resulting in their first recording Communication.
After the Guild discontinued its activities, he toured Europe twice during 1965/66 with the Jazz Realities Quintet, featuring Steve Lacy and Carla Bley. He then established the Jazz Composer's Orchestra Association, a non-profit organization to commission, perform, and record new compositions for jazz orchestra.
He recorded a double album of his music during 1968 with the Jazz Composer's Orchestra and soloists Cecil Taylor, Don Cherry, Roswell Rudd, Pharoah Sanders, Larry Coryell, and Gato Barbieri. Some of this music was also performed during the "Long Concerts" at the Electric Circus in 1969.
He appeared as trumpet player on Carla Bley's A Genuine Tong Funeral, recorded by Gary Burton, and also on Charlie Haden's Liberation Music Orchestra album (1969).
He co-ordinated and participated in the Jazz Composer's Orchestra's next recording project, Carla Bley's Escalator Over The Hill (1968-71).
The problems of independently distributing the orchestra's record label led him to form the New Music Distribution Service in 1972, an organization which was to serve many independent labels for almost 20 years.
In 1973 he started WATT WORKS, a new record label devoted to the presentation of his and Carla Bley's music exclusively. He recorded No Answer, featuring Jack Bruce, for which he wrote music to the words of Samuel Beckett.
The following year he built a recording studio near Woodstock, N.Y. to escape the pressures of commercial recording studios. He received composition grants from the Creative Artists Program Service and the National Endowment for the Arts, and with the aid of a Ford Foundation grant he was able to undertake the recording of his 13 for two orchestras and piano (1975).
He wrote and recorded several more albums for WATT: The Hapless Child, with words by Edward Gorey, featuring Robert Wyatt (1976), Silence, based on the Harold Pinter play, again with Robert Wyatt (1976), Movies, with Larry Coryell and Tony Williams (1977), and More Movies, with Philippe Catherine (1980). During that period he also appeared on albums by John Greaves (Kew Rhone) and Nick Mason (Fictitious Sports), and then toured briefly with his own small group.