In 1962 he signed his first record with Bill Dixon as co-leader. During the following year, he created the New York Contemporary Five with John Tchichai, made four records for Fontana, Storyville and Savoy and travelled to Europe with this group. Starting in August 1964, he worked with Impulse and made 17 records among which, Four For Trane, Fire Music, and Mama Too Tight, some of the classics of Free Music. His collaboration with John Coltrane materialized further with Ascension in 1965, a real turning point in Avant-Garde music. His militancy was evidenced by his participation in the creation of the Composers Guild with Paul and Carla Bley, Sun RA, Roswell Rudd and Cecil Taylor.