John Ritter Jack Tripper Actor Joyce DeWitt Janet Wood Actor Priscilla Barnes Terri Alden Actor Richard Kline Larry Dallas Actor Don Knotts Ralph Furley Actor Mary Cadorette Guest Star David Ruprecht Guest Star Henry Sutton Guest Star Robert Clotworthy Guest Star K.C. Winkler Guest Star Robert Mandan Guest Star Michael Ross Executive Producer, Writer Bernie West Executive Producer, Writer George Burditt Executive Producer, Writer Martin Rips Producer, Writer Joseph Staretski Producer, Writer George Sunga Producer Dave Powers Director