Campbell's first television appearance was at the age of six, in an episode in 1974 of the PBS show "The Big Blue Marble". As a child, she won many talent shows, going on to appear in such children's programs as "Kids Are People Too", "Unicorn Tales" (played lead Daisy Bunsen in episode, "The Magnificent Major"), and "Captain Kangaroo". At age 16, she performed in the musical feature film, "Little Shop of Horrors" as Chiffon, one of The Supremes like girl group Greek Chorus, along with future "Martin" co star, Tichina Arnold.