Ralph has appeared in a number of movies during her career. In 1991, she received Independent Spirit Award for Best Supporting Female for her role in the drama film "To Sleep with Anger". Her other film credits include "The Mighty Quinn" (1989), "The Distinguished Gentleman" (1992), "" (1993), and "Deterrence" (1999). On television, Ralph starred from 1986 to 1989 in the syndicated sitcom "It's a Living", and later had the leading roles in the short-lived ABC sitcom "New Attitude" (1990), and CBS medical drama "Street Gear" (1995). From 1996 to 2001, she starred as Dee Mitchell in the UPN sitcom "Moesha", and from 2013 to 2015 as Maggie Turner in the Nick at Nite sitcom "Instant Mom".