Born in Joliet, Illinois, Thigpen obtained a degree in teaching. She taught English in high school briefly while studying theatre and dance at the University of Illinois. Thigpen moved to New York City in 1971 to begin her career as a stage actress. She had a long and prolific theater career, and appeared in numerous musicals including Godspell, The Night That Made America Famous, The Magic Show, Working, Tintypes and An American Daughter (for which she won her Tony Award for her portrayal of Dr. Judith Kaufman in 1997). Her first feature film role was Lynne in Godspell (1973), co-starring opposite Victor Garber and David Haskell. She appeared notably as the omniscient Radio DJ in The Warriors, and as Leonna Barrett, the mother of an expelled student in Lean on Me, a story of famous American high school principal Joe Louis Clark. She had a role in Shaft, alongside Samuel L. Jackson, as Carla Howard, the murder victim’s mother. She also played the Second President of the World Congress in Bicentennial Man (1999). Her last film was Anger Management (2003), starring Adam Sandler and Jack Nicholson (which was released only a month following her death and paid tribute to her in the end credits).

Thigpen was perhaps best known for playing Luna in the television show, Bear in the Big Blue House as well as “The Chief” of the ACME Detective Agency in the long-running PBS children’s geography game show Where in the World Is Carmen Sandiego?, which involves both education and comedy, and, on occasion, musical performance. She remained The Chief in the successor show, Where in Time is Carmen Sandiego?, but of ACME Time Net. She also appeared in many other television series during her career, most notably in a recurring role as Grace Keefer on the ABC daytime drama All My Children and a supporting role as Ella Mae Farmer, a statistics clerk for the Washington, D.C. police department, on the CBS crime drama The District. She guest-starred in episodes of Gimme A Break!, L.A. Law, Law & Order, The Days and Nights of Molly Dodd, Homicide: Life on the Street, and Thirtysomething. She appeared in radio skits of the Garrison Keillor program The American Radio Company of the Air. Her voice was also heard on over 20 audio books, primarily works with socially relevant themes.

Thigpen died of a cerebral hemorrhage on March 12, 2003, in her Marina del Rey, California, home after complaining of headaches for several days. Drugs and foul play were ruled out by the coroner’s autopsy, which found “acute cardiac dysfunction, non-traumatic systemic and spontaneous intraventricular hemorrhage and hemorrhage in the brain.” She was entombed next to her parents at Elmhurst Cemetery in her hometown of Joliet, Illinois.