Newsom, who died Saturday, had bladder and liver cancer, The Washington Post said Monday.
Dubbed "Mr. Excitement" by the late late-night talk show host, Newsom pretended he had little personality in response to Carson's barbs.
A jazz musician, Newsom played with guitarist Charlie Byrd, clarinetist Benny Goodman and bandleader Vincent Lopez.
At NBC, he was a studio musician who was assigned to the "Tonight" show in 1962.
Newsom spent the next three decades on the show, most of the time working under bandleader and trumpeter Doc Severinsen. Newsom became assistant music director in the late 1960s, handling the baton in Severinsen's absence.
His parents bought him a saxophonist at 8 and by 13, Newsom was playing professional engagements in the Norfolk, Va., area.
Newsom's "Titter Pipes" became a showcase number for saxophonists Phil Woods and Zoot Sims.
Newsom arranged for Byrd, jazz trumpeter Buck Clayton and the all-female jazz orchestra Diva, among others.
Newsom shared Emmys for his musical arrangements for "Night of 100 Stars II" and the "40th Annual Tony Awards."