Members of Jon and Lee & The Checkmates ultimately formed the nucleus of the later bands Rhinoceros and Blackstone, plus contributed significantly to the work of Lou Reed in the 1970s.
When Jon and Lee & The Checkmates broke up in September 1967, Fonfara worked briefly with David Clayton-Thomas and then, during the months of November and December, 1967, toured and recorded with The Electric Flag, featuring Buddy Miles and Michael Bloomfield.
Upon the dissolution of Rhinoceros in 1971, Fonfara joined with ex-Rhinoceros bandmates John Finley, Danny Weis, Larry Leishman and Peter Hodgson to form the group Blackstone.
He left the band at the end of 1977 in a dispute over payment for his work on Rough Trade's live revue show Restless Underwear.
He married model Avril Lund (born 1950) and had two children with her before he died on 8 January 2021 at 74 in a Toronto hospital, following a two-year battle with cancer.