Cantor was raised in Pleasantville, New York and attended Indiana University, the Guildhall School of Music and Drama, and the American Academy of Dramatic Arts.
The New York Times later wrote on July 14, 1985, of Cantor's performance in a regional theatre production of Evita: "David Cantor, a veteran in the part, is a marvelous Che, never lapsing into excessive snideness, singing gorgeously and, at times, sailing into the stratosphere with his crystalline 'high-flying, adored' pianissimi.
His other stage credits include Benedick in Much Ado About Nothing (1978); Tony Lumpkin in She Stoops to Conquer (1978); Infielder in Damn Yankees with Starlight Theatre in Kansas City, Missouri (1978); Matt in The Fantasticks in a production directed by the show's creators, Tom Jones and Harvey Schmidt (1982); The Princess Pat (1981); John Adams in 1776 (1982); Charlie in Tintypes (1986); Stanley Jerome in both Brighton Beach Memoirs (1986) and Broadway Bound (1987); Seymour in Little Shop of Horrors (1987); Vernon Gersch in They're Playing Our Song (1988); Benny in The Desert Song at North Shore Music Theatre (1988).
[4] Cantor has performed principal roles in all of the Gilbert and Sullivan comic operas in the U.S., Great Britain, and Italy.
In the early 1980s, he played a number of television soap opera roles in All My Children, Loving, Another World, and Ryan's Hope.