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 David Ruprecht Guest Star Mary Cadorette Guest Star Sondra Currie Guest Star Gerald Hiken Guest Star William Cort Guest Star Richard Karron Guest Star Henry Sutton Guest Star Fran Ryan Guest Star Michael Ensign Guest Star Toni Sawyer Guest Star Robert Clotworthy Guest Star Dallas Alinder Guest Star Robert Mandan Guest Star K.C. Winkler Guest Star Tom Lancaster 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 David Mirkin Writer Sandy Krinski Writer Michael Weinberger Writer Ron Bloomberg Writer Mark Tuttle Writer Arlan Gutenberg Writer Chet Dowling Writer Al Gordon Writer