Raised in the US before relocating to Britain, Leon is credited with the discovery and early development of groups like the Talking Heads, The Ramones, Blondie, Richard Hell & The Voidoids, and Suicide. Later years saw the record producer revisiting the classicism of his early music training, with his compositions, orchestration, and arrangement contributing to recordings of Italian soprano Giorgia Fumanti and The Royal Philharmonic and London Symphony orchestras. He has also scored a number of feature films.

Leon's keen ear for anticipating advancements in sound and style is also shown in his electronic productions, which preceded the rise of industrial music, new age, and ambient techno. Released on John Fahey's Takoma label in 1980, his Nommos LP was conceptually designed around the creation myth of the Dogon tribe of Mali, with its "interplanetary folk" style of cosmic sound washes and metallic polyrhythms loosely adapted from the most basic modes and rhythms of West African music. Visiting, also produced with Leon's growing collection of synthesizers, followed on Enigma in 1982. Intended as a two-part "mirror image" set, both albums were reissued in the summer of 2014 by RVNG International. Nommos will be presented in Germany for the first time at CTM 2015, in collaboration with Texas folk artist Cassell Webb and an acoustic ensemble.

Leon's current composition projects combine synthesizers and orchestral instruments, and outings on Sony Masterworks and Atlas Realisations are planned for 2015 and 2016.