A superior bassist, Jay Leonhart has also had a parallel and sometimes overlapping career as a witty lyricist and occasional singer. As a child he attended the Peabody Conservatory (1946-50) and by the time he went to the Berklee College of Music (1959-61), Leonhart was a jazz musician. He played with Buddy Morrow (1961) and Mike Longo (1962-63) and then became a busy freelance musician in New York. Among Leonhardt's many associations were Marian McPartland (with whom he recorded in 1971), Jim Hall, Urbie Green, Chuck Wayne (1976), Phil Woods, Gerry Mulligan, Lee Konitz, Don Sebesky, Louie Bellson and pianist Mike Renzi. Leonhart started becoming well-known as a lyricist in the 1980's when he began leading his own recording sessions and started having his songs being recorded by other singers.