Gunn rarely had comparable roles to showcase his talents in films but his large, regal features and booming yet somewhat raspy voice stood out during his 25-year film career. Gunn may be best remembered as Bumpy Jonas, the powerful Harlem gangster whose daughter is kidnapped in Gordon Parks' "Shaft" (1971). He reprised that role in Parks' "Shaft's Big Score" (1972). Gunn was also memorable as Booker T. Washington in "Ragtime" (1981). His last major film was Clint Eastwood's "Heartbreak Ridge" (1986) in which he played aging vet Sergeant Webster.
Gunn also worked extensively in TV. He was nominated for an Emmy for his portrayal of African chief Kintango in the first installment of "Roots" (ABC, 1977). Gunn joined the cast of the hit CBS sitcom, "Good Times" in 1977 as Carl Dixon, the appliance store owner who marries the widowed Esther Rolle and whisks her away from the projects. He was also a guest star on numerous series including "The Cosby Show", "Equal Justice" and "Homicide".