A former journalist in Minnesota, he got an acting job while on assignment for a story about a workshop theatre and stayed with the improvisational company for two years.
Both he and friend Danny Glover made their feature film debuts in Escape from Alcatraz (1979).
Has a son, Brandon Lumbly (born 1988) with Vonetta McGee.
Long-time close friend of Danny Glover, they appeared together in two of Athol Fugard's plays early in their career: "Siswe Bansi Is Dead" and "The Island". Carl recently appeared in the film Just a Dream (2002) directed by Glover.
Played an alien in The Adventures of Buckaroo Banzai Across the 8th Dimension (1984)) and voiced the alien Martian Manhunter/J'onn J'onzz on the animated "Justice League" (2001).
Went to same college as Peter Berg - Macalester College, Saint Paul, Minnesota. He appeared in a guest role with Berg in episode #2.17, "Life Lines" of "Chicago Hope" (1994). Berg also guest starred in two episodes of "Alias" (2001) where Lumbly had a big role.