In the mid-1960s, Wheeler became a close participant in the nascent free improvisation movement in London, playing with John Stevens Parker, the Spontaneous Music Ensemble and the Globe Unity Orchestra.
Wheeler was the trumpet player in the Anthony Braxton Quartet from 1971 to 1976, and from 1977 he was also a member of the chamber jazz group Azimuth (with John Taylor and Norma Winstone).