She started acting in the early seventies, her first movie appearance being Don’t Play Us Cheap in 1973 as a house guest. Estelle Rolle also appeared in the movie. She also played Evillene, the evil witch of the west, in both the movie and broadway versions of Diana Ross’ The Wiz. She even played Steve Martin’s mother in The Jerk in 1979. But of course, Mabel would always be known as Ms. Thomas on the seventies sitcom “What’s Happening!!” along with Ernest Thomas, Haywood Nelson, Fred Berry, Danielle Spencer and Shirley Hemphill. She left the show in 1978 though because she wanted to have her character get remarried and she also wanted her salary to be raised. When the producers refused she quit and the show was canceled the season after. Many people say the last season wasn’t nearly as good due to the loss of Mabel on the show though it was brought back in 1985 under the title “What’s Happening Now!”, once again without Mabel.
She went on with her career making TV guest appearances on “The Jeffersons”, “Wiseguy”, “Barney Miller” and even “Match Game”. She also appeared in The Gong Show Movie (1980), The Jerk, Too (1984) and Scrooged (1988).
She ran into trouble when she was diagnosed with diabetes in the mid-eighties. She first lost a toe in 1986 and then both her legs and an arm later on. She had a stroke in 1989 leaving her left side paralyzed and was speechless for over a year. She had to be in a wheelchair and had found it difficult to do the simpliest things. She almost died in the early nineties during surgery to have her hip replaced.
Her son, Larry, died in 1996 of cirrhosis. He had troubles with drugs and used to scam his mother out of money.
Mabel lived at The Motion Picture Country Home in Woodhills, California. There an ambulance crew once dropped her which injured her even more and once fell out of her wheelchair and landed on the floor, face first, losing some of her top teeth. Friends raised money for her and they eventually raised enough to get her a brand new wheelchair.
She later moved to a house also in Woodland Hills on Exhibit Court which belonged to her attorney. She had to go to Kaiser Foundation Hospital in 1999 due to dialysis and on November 9, 1999 her kidneys failed and she passed away at age 66. She was cremated and her ashes were given to her attorney.