Ralph began her career on the stage, and was nominated in 1982 for a Tony Award for Best Actress in a Musical for her role as Deena Jones in "Dreamgirls". In 1984, Ralph released her only album "In the Evening", in which the title track peaked at No. 6 on the "Billboard" "Dance Music/Club Play Singles" chart that same year. In 1988 she starred in the Disney movie "Oliver & Company", providing the voice of Rita. Her first leading role in a film came as Denzel Washington's wife in "The Mighty Quinn", released in 1989. In 1992 she starred with Robert De Niro in the title role in "Mistress". That same year, she co-starred with Eddie Murphy in "The Distinguished Gentleman". During the 1990s she also had roles in "The Flintstones", "Deterrence", and "Unconditional Love".