After leaving college, Martin moved to Chicago, and New York City thereafter to study acting with the WPA Theater and the Rose McClendon Players. She was a founding member of the American Negro Theater in Harlem. Martin became a Broadway character actress for many decades, debuting in 'Orchids Preferred' in 1937 and thereafter Orson Welles's production of Native Son in 1941.
Martin appeared in a dozen Broadway shows, including Jean Genet's The Blacks, the musical Raisin from 1973 until 1975, Ossie Davis's Purlie Victorious (and later the musical version, which was called Purlie), The Amen Corner and Tennessee Williams's Period of Adjustment.
Martin became widely known later in life due to her roles in popular television series, which brought her a large audience. She had a recurring role as Wanda "Weeping Wanda" Williams on the television series Good Times, and later as the neighbor Pearl Shay on the television sitcom 227, which lasted from 1985 until 1990. Martin also had a role on the short-lived sitcoms Baby, I'm Back (as mother in-law, Luzelle) and That's My Mama. Martin portrayed a variety of grandmothers in films: (1987), (1996), I Got the Hook Up (1998), House Party 2 (1991), and Mama Doll in (1998).