Glenn's career spanned five decades, beginning in radio with shows such as Amos 'n Andy and The Jack Benny Show. He made numerous appearances on television, from its early days until 1970. Widely reported as the original voice of "Tony the Tiger" in Kellogg's Sugar Frosted Flakes in Kellogg's Sugar Frosted Flakes commercials in the early 1950s. Kellogg's, however, maintains that Thurl Ravenscroft was the original voice from the early 1950s.
His first film appearance was in 1937; his career included roles in A Raisin in the Sun (1961), with Sidney Poitier, Ruby Dee and Claudia McNeil, and a memorable turn as Mr. Prentice, (again playing opposite Poitier) in the 1967 feature film Guess Who's Coming to Dinner. Roy Glenn's last big screen appearance was in Support Your Local Gunfighter (1971).
