Born in Brooklyn, New York, on August 5, 1945 and raised on Long Island, DuBois got her start in theater, appearing in a number of plays including Golden Boy with Sammy Davis. Jr. and Lou Gossett Jr. In 1969, she won a Peabody Award for the CBS children's movie, J.T. By 1970, she'd been cast in the TV soap opera Love of Life as Loretta Allen, a role that made her the first African American actress to have a series regular role on a daytime soap.
It was her role on Good Times that made her a TV star; as Willona, she traded barbs with the series' leading men, nurtured the Evans kids and remained happily independent for most of the series. She went on to appear in many more shows and films throughout her career, including guest spots on Moesha, Hangin' With Mr. Cooper, Touched By An Angel, and Everybody Loves Raymond, and roles in films including the Wayans' blaxploitation parody I'm Gonna Git You Sucka and Heart Condition in 1990 with Denzel Washington.
She won two Emmys for voice over work on The PJs and lent her talents as a singer-songwriter to compose and sing the theme song, "Movin' On Up," for Norman Lear's other landmark sitcom, The Jeffersons.