| Year,Title,Role,Notes | |
| 1955,The Vise,Tony Mason,"1 episode (""Gift from Heaven"")" | |
| 1958,The Vise,Vance,"1 episode (""Blood in the Sky"")" | |
| 1958,Armchair Theatre,Jack 'Pal' Smurch,"1 episode (""The Greatest Man in the World"")" | |
| 1959,Brand,Priest Brand,Henrik Ibsen play | |
| 1961,Armchair Theatre,Nicholai Soloviov,"1 episode (""The Man Out There"")" | |
| 1960–62 1964–67,Danger Man,John Drake,39 + 47 episodes. Also directed three episodes. | |
| 1963,Walt Disney's Wonderful World of Color,Doctor Christopher Syn/ Scarecrow of Romney Marsh,3 episodes | |
| 1967–68,The Prisoner,Number Six,17 episodes. Also directed five episodes. | |
| 1969,Journey into Darkness,Host,Made-for-TV film | |
| 1974,Columbo,Colonel Lyle C. Rumford,"1 episode (""By Dawn's Early Light"")" | |
| 1975,Columbo,Nelson Brenner,"1 episode (""Identity Crisis""). Also directed." | |
| 1976,Columbo,N/A,"1 episode (""Last Salute to the Commodore"") – director" | |
| 1977,Rafferty,Doctor Sid Rafferty,13 episodes. Also directed one episode. | |
| 1979,The Hard Way,John Connor,Made-for-TV film | |
| 1983,Jamaica Inn,Joss Merlyn,- | |
| 1985,American Playhouse,Chief magistrate,"3 episodes (""Three Sovereigns for Sarah"" parts I, II & III)" | |
| 1987,"Murder, She Wrote",Oliver Quayle,"1 episode (""Witness for the Defense"")" | |
| 1990,Columbo,Oscar Finch,"1 episode (""Agenda for Murder""). Also directed." | |
| 1998,Columbo,Eric Prince,"""Ashes to Ashes"". Also directed." | |
| 2000,Columbo,N/A,"1 episode (""Murder with Too Many Notes"") – director" | |
| 2000,The Simpsons,Number Six,"1 episode (""The Computer Wore Menace Shoes"")" | |