Mom P.I. is a 1990-92 Canadian television comedy-drama series starring Rosemary Dunsmore, Stuart Margolin, Emily Perkins, and Shane Meier.Dunsmore plays eternal optimist Sally Sullivan, a recently widowed mother of two supporting her family as a waitress in a working-class diner, who talks her way into a job as assistant to grumpy, cynical private eye Bernie Fox, played by The Rockford Files' Margolin.