Born on December 18, 1938, in Los Angeles, California, and raised by his mother, Eloise, Mosley grew up in the Imperial Courts public housing in the Watts neighborhood.

Other actors in the feature were Phyllis Davis, Don Marshall, Ena Hartman, and Tom Selleck,[4] who would later star in the television series Magnum, P.I.

[6] Mosley's most prominent film role was his 1976 starring turn as the title character in Leadbelly, a biography of the musician directed by Gordon Parks.

"[11] Mosley guest-starred on such shows as Night Court,[13] Kung Fu, Starsky & Hutch, Kojak, The Rockford Files, Baretta, and Sanford and Son.

[15] He appeared in other blaxploitation films of the period, including Hit Man (1972); Sweet Jesus, Preacherman (1973); Darktown Strutters (1975); and The River Niger (1976).

Mosley's other film credits include McQ (1974) with John Wayne,[16] The Greatest (1977, as Sonny Liston), Semi-Tough (1977), Heart Condition (1990), and Pentathlon (1994).

[17] He also starred in the television series Hangin' with Mr. Cooper (1992–1993) as Coach Ricketts in a recurring role with comedian/actor Mark Curry, and in the film A Thin Line Between Love and Hate (1996) with Martin Lawrence, Lynn Whitfield, and Bobby Brown.

[22] On August 4, 2022, Mosley was involved in a major car crash in Lynwood, California, leaving him in critical condition, paralyzed from the shoulders down.