| 2024 | « La Planète des singes » : une odyssée de l'espèce | Self (archive footage) |
| 2024 | Elizabeth Taylor: The Lost Tapes | Self (archive footage) |
| 2001 | Cleopatra: The Film That Changed Hollywood | Self (archive footage) |
| 2001 | The Return of Captain Sinbad | Narrator |
| 2000 | Mary Pickford: A Life on Film | Self |
| 2000 | Backstory: 'How Green Was My Valley' | Self (archive footage) |
| 1999 | Keepers of the Frame | Himself |
| 1999 | Linda Darnell: Hollywood's Fallen Angel | |
| 1998 | Život Buba | Mr. Soil (voice) |
| 1998 | Godzilla: The Series | |
| 1998 | Behind the Planet of the Apes | Self - Hosted by (also archive footage) |
| 1998 | Louise Brooks: Looking for Lulu | Himself - Actor / Friend |
| 1998 | Loss of Faith | Henry Stokes |
| 1998 | Something to Believe In | Gambler |
| 1998 | Star Power: The Creation Of United Artists | Narrator (voice) |
| 1997 | The New Batman Adventures | Mad Hatter (voice) |
| 1997 | The New Batman Adventures | The Mad Hatter / Jervis Tetch (voice) |
| 1997 | The Second Jungle Book: Mowgli & Baloo | King Murphy |
| 1997 | Obsessed with Vertigo: New Life for Hitchcock's Masterpiece | Narrator (Voice) |
| 1997 | Vincent Price: The Versatile Villain | Self |
| 1997 | Twentieth Century Fox: The First 50 Years | Self |
| 1997 | Walter Matthau: Diamond in the Rough | Self |
| 1997 | Audrey Hepburn: The Fairest Lady | Self |
| 1997 | Barbara Stanwyck: Straight Down The Line | Self |
| 1997 | Henry Fonda: Hollywood's Quiet Hero | Self |
| 1996 | Superman: The Animated Series | Mad Hatter (voice) |
| 1996 | It's My Party | Damian Knowles |
| 1996 | Unlikely Angel | Saint Peter |
| 1996 | Star Hunter | Riecher |
| 1996 | Dead Man's Island | Trevor Dunnaway |
| 1995 | Pinky and the Brain | Snowball (voice) |
| 1995 | The Grass Harp | Amos Legrand |
| 1995 | Last Summer in the Hamptons | Thomas |
| 1995 | The Alien Within | Dr. Henry Lazarus |
| 1995 | Darryl F. Zanuck: 20th Century Filmmaker | Self |
| 1994 | Gargoyles | |
| 1994 | Mirror Mirror 2: Raven Dance | Dr. Lasky |
| 1994 | Angel 4: Undercover | Geoffrey Kagen |
| 1994 | Hart to Hart: Home Is Where the Hart Is | Jeremy Sennet |
| 1994 | Heads | Fibris Drake |
| 1994 | Burke's Law | Maurice Gillette |
| 1994 | The Story of Lassie | Self |
| 1994 | Meet Me in St. Louis: The Making of an American Classic | Narrator (voice) |
| 1994 | Biography: Bette Davis — If Looks Could Kill | Self |
| 1993 | SWAT Kats: The Radical Squadron | |
| 1993 | The Evil Inside Me | Pauly |
| 1992 | Batman: Crtana serija | Mad Hatter (voice) |
| 1992 | Double Trouble | Phillip Chamberlin |
| 1992 | MGM: When the Lion Roars | |
| 1992 | The Naked Target | Ernest Peabody |
| 1992 | The Magical World of Chuck Jones | Self |
| 1992 | The Sands of Time | Alan Tucker |
| 1991 | The Pirates of Dark Water | Niddler (voice) |
| 1991 | Earth Angel | Mr. Tatum |
| 1991 | The Legend of Prince Valiant | |
| 1991 | Going Under | Secretary Neighbor |
| 1991 | Deadly Game | Dr. Aaron |
| 1991 | Timmy's Gift: A Precious Moments Christmas | Narrator (voice) |
| 1991 | An Inconvenient Woman | Cyril Rathbone |
| 1991 | Crazy About the Movies: Dennis Hopper | Self |
| 1990 | Shakma | Sorenson |
| 1990 | Dream On | Bob Jeffers |
| 1990 | The Color of Evening | Henry Seaton |
| 1989 | Quantum Leap | Edward St. John V |
| 1989 | Cutting Class | Mr. Dante |
| 1989 | The Big Picture | Judge |
| 1989 | Put oko svijeta za 80 dana | McBaines |
| 1989 | The New Lassie | |
| 1989 | Camp Candy | |
| 1989 | Harold Lloyd: The Third Genius | Self |
| 1989 | Nightmare Classics | Inspector Amos |
| 1989 | Carmilla | Inspector Amos |
| 1989 | Hollywood on Horses | Self |
| 1988 | Fright Night Part 2 | Peter Vincent |
| 1988 | Doin' Time on Planet Earth | Minister |
| 1988 | Remo Williams: The Prophecy | |
| 1987 | Lažna žena iz mora | Andrew |
| 1987 | Dead of Winter | Mr. Murray |
| 1986 | Matlock | |
| 1986 | The Wizard | |
| 1986 | GoBots: Battle of the Rock Lords | Nuggit (voice) |
| 1986 | Bridges to Cross | |
| 1985 | Fright Night | Peter Vincent |
| 1985 | Alice in Wonderland | The March Hare |
| 1985 | Hollywood Wives | Jason Swandle |
| 1984 | Murder, She Wrote | Dr. Alger Kenyon, PHD |
| 1984 | Murder, She Wrote | Gordon Fairchild |
| 1984 | The Zany Adventures of Robin Hood | Prince John |
| 1983 | The Wind in the Willows | Ratty (voice) |
| 1983 | This Girl For Hire | Manfred Hayes |
| 1983 | Rapunzel | Narrator |
| 1982 | Evil Under the Sun | Rex Brewster |
| 1982 | Class of 1984 | Terry Corrigan |
| 1982 | Tales of the Gold Monkey | "Bon Chance" Louie |
| 1982 | Hotel | |
| 1982 | Faerie Tale Theatre | Narrator (voice) |
| 1982 | Mae West | Rene Valentine |
| 1982 | The Making of Agatha Christie's 'Evil Under the Sun' | Self / Rex Brewster |
| 1982 | Twilight Theatre | Self - Host |
| 1982 | Hollywood’s Children | Self (Narrator) |
| 1981 | Charlie Chan and the Curse of the Dragon Queen | Gillespie |
| 1981 | The Million Dollar Face | Derek Kenyon |
| 1980 | Povratak kralja | Samwise Gamgee (voice) |
| 1980 | The Martian Chronicles | Father Stone |
| 1980 | Back to the Planet of the Apes | Galen |
| 1980 | Farewell to the Planet of the Apes | Galen |
| 1980 | The Forgotten City of the Planet of the Apes | Galen |
| 1980 | Life, Liberty and Pursuit on the Planet of the Apes | Galen |
| 1980 | Treachery and Greed on the Planet of the Apes | Galen |
| 1980 | Here's Boomer | |
| 1980 | The Memory of Eva Ryker | MacFarland |
| 1979 | Crna rupa | V.I.N.CENT. (voice) (uncredited) |
| 1979 | Hart to Hart | Dr. Peterson |
| 1979 | Buck Rogers u 25. stoljeću | Governor Saroyan |
| 1979 | Scavenger Hunt | Jenkins |
| 1979 | Trapper John, M.D. | |
| 1979 | Sitcom: The Adventures of Garry Marshall | Chuck the Robot (voice) |
| 1979 | Hart to Hart | Dr. Peterson |
| 1979 | Sweepstakes | |
| 1978 | The Cat from Outer Space | Mr. Stallwood |
| 1978 | Laserblast | Doctor Mellon |
| 1978 | Circle of Iron | White Robe |
| 1978 | Rabbit Test | Gypsy Grandmother / Dr. D & C Fishbine |
| 1978 | The Thief of Baghdad | Hasan |
| 1978 | Flying High | |
| 1978 | The Immigrants | Mark Levy |
| 1977 | The Love Boat | Fred Beery |
| 1977 | Flood! | Mr. Franklin |
| 1977 | The Fantastic Journey | Dr. Jonathan Willoway |
| 1977 | The Rhinemann Exchange | Bobby Ballard |
| 1977 | Sixth and Main | Skateboard |
| 1976 | That's Entertainment, Part II | (archive footage) |
| 1976 | Embryo | Frank Riley |
| 1976 | Mowgli's Brothers | Mowgli (voice) |
| 1976 | It's Showtime | Self (archive footage) |
| 1975 | Wonder Woman | Henry Roberts |
| 1975 | Funny Lady | Bobby Moore |
| 1975 | Ellery Queen | |
| 1975 | The White Seal | Narrator/ White Seal |
| 1975 | Mean Johnny Barrows | Tony Da Vince |
| 1975 | Elizabeth Taylor: An Intimate Portrait | Self |
| 1974 | Dirty Mary Crazy Larry | George Stanton (uncredited) |
| 1974 | Planet majmuna | Galen |
| 1974 | Police Woman | |
| 1974 | Harry O | |
| 1974 | The Elevator | Marvin Ellis |
| 1973 | Battle for the Planet of the Apes | Caesar |
| 1973 | The Legend of Hell House | Benjamin Franklin Fischer |
| 1973 | Barnaby Jones | Stanley Lambert |
| 1973 | Arnold | Robert |
| 1973 | Miracle on 34th Street | Dr. Sawyer |
| 1973 | The Snoop Sisters | Lionel Standish |
| 1973 | The American Film Institute Salute to ... | Self |
| 1972 | Conquest of the Planet of the Apes | Caesar |
| 1972 | Posejdonova avantura | Acres |
| 1972 | The Life and Times of Judge Roy Bean | Frank Gass |
| 1972 | The Rookies | |
| 1972 | Hollywood: The Dream Factory | Self (archive footage) |
| 1972 | Corky | Harassed Salesman |
| 1971 | Escape from the Planet of the Apes | Cornelius |
| 1971 | Bedknobs and Broomsticks | Mr. Jelk |
| 1971 | Columbo | Roger Stanford |
| 1971 | Pretty Maids All in a Row | Mr. Proffer |
| 1971 | A Taste of Evil | Dr. Michael Lomas |
| 1971 | Great Performances | Self |
| 1971 | Terror in the Sky | Dr. Ralph Baird |
| 1971 | What's a Nice Girl Like You...? | Albert Soames |
| 1971 | Journey to Murder | Rollo Verdew |
| 1970 | Night Gallery | Jeremy Evans |
| 1970 | McCloud | |
| 1969 | Night Gallery | Jeremy Evans |
| 1969 | Love, American Style | Howard |
| 1969 | Hello Down There | Nate Ashbury |
| 1969 | Angel, Angel, Down We Go | Santoro |
| 1969 | Midas Run | Wister |
| 1968 | Planet of the Apes | Cornelius |
| 1968 | 5 Card Stud | Nick Evers |
| 1968 | The Name of the Game | Philip Saxon |
| 1968 | The Name of the Game | Early McCorley |
| 1968 | Journey to the Unknown | |
| 1967 | Ironside | |
| 1967 | The Carol Burnett Show | Self - Guest |
| 1967 | The Carol Burnett Show | Self - Guest / Various Characters |
| 1967 | The Invaders | Lloyd Lindstrom |
| 1967 | The Adventures of Bullwhip Griffin | Bullwhip Griffin |
| 1967 | It! | Arthur Pimm |
| 1967 | Cricket on the Hearth | Cricket Crocket (voice) |
| 1967 | The Cool Ones | Tony Krum |
| 1967 | Saint Joan | Charles, The Dauphin |
| 1966 | Batman | The Bookworm |
| 1966 | Mission: Impossible | |
| 1966 | Lord Love a Duck | Alan Musgrave |
| 1966 | L'espion | Agent Adams |
| 1966 | Felony Squad | |
| 1965 | Najveća priča ikad ispričana | Matthew |
| 1965 | That Darn Cat! | Gregory Benson |
| 1965 | Inside Daisy Clover | Walter Baines |
| 1965 | The Loved One | D.J. Jr. |
| 1965 | The Third Day | Oliver Parsons |
| 1965 | Run for Your Life | Gyula Bognar |
| 1964 | Shock Treatment | Martin Ashley |
| 1963 | Kleopatra | Octavian - Caesar Augustus |
| 1963 | Bob Hope Presents the Chrysler Theatre | Arthur Biddle |
| 1963 | Kraft Suspense Theatre | Robert 'Professor' Benson |
| 1963 | The Danny Kaye Show | Self |
| 1963 | Arrest and Trial | |
| 1963 | The Power and the Glory | Mestizo |
| 1962 | The Longest Day | Pvt. Morris |
| 1962 | The Tonight Show Starring Johnny Carson | Self |
| 1962 | The Alfred Hitchcock Hour | George |
| 1962 | The Alfred Hitchcock Hour | Gerald Musgrove |
| 1962 | The Merv Griffin Show | Self |
| 1961 | Ben Casey | |
| 1960 | Midnight Lace | Malcolm |
| 1960 | The Subterraneans | Yuri Gilgoric |
| 1960 | The Tempest | Ariel |
| 1959 | The Twilight Zone | Sam Conrad |
| 1958 | Velika zemlja | Hannassey Watchman (uncredited) |
| 1958 | Naked City | Donnie Benton |
| 1958 | Heart of Darkness | Charles Marlow |
| 1957 | Suspicion | |
| 1955 | Matinee Theater | |
| 1953 | General Electric Theater | Leprechaun |
| 1952 | The Steel Fist | Eric Kardin |
| 1951 | Hallmark Hall of Fame | |
| 1951 | Hallmark Hall of Fame | Ariel |
| 1951 | Hallmark Hall of Fame | The Dauphin |
| 1950 | Lux Video Theatre | Pete |
| 1950 | Robert Montgomery Presents | Gerald Forbes |
| 1950 | Lux Video Theatre | Bellamy Partridge |
| 1950 | Robert Montgomery Presents | Pip |
| 1950 | Killer Shark | Ted White |
| 1950 | Everybody's Dancin' | Roddy McDowall |
| 1950 | Big Timber | Jimmy |
| 1949 | Black Midnight | Scott Jordan |
| 1949 | Tuna Clipper | Alec MacLennan |
| 1948 | Macbeth | Malcolm |
| 1948 | The Ed Sullivan Show | Self / Ariel |
| 1948 | Kidnapped | David Balfour |
| 1948 | Rocky | Chris Hammond |
| 1946 | Holiday in Mexico | Stanley Owen |
| 1945 | Molly and Me | Jimmy Graham |
| 1945 | Thunderhead: Son of Flicka | Ken McLaughlin |
| 1944 | The Keys of the Kingdom | Francis Chisholm, as a boy |
| 1944 | The White Cliffs of Dover | John Ashwood II as a Boy |
| 1943 | Lassie Come Home | Joe Carraclough |
| 1943 | My Friend Flicka | Ken McLaughlin |
| 1942 | Son of Fury: The Story of Benjamin Blake | Benjamin - as a Boy |
| 1942 | The Pied Piper | Ronnie Cavanaugh |
| 1942 | On the Sunny Side | Hugh Aylesworth |
| 1941 | How Green Was My Valley | Huw Morgan |
| 1941 | Man Hunt | Vaner |
| 1941 | This England | Hugo |
| 1941 | Confirm or Deny | Albert Perkins |
| 1941 | You Will Remember | Young Bob Slater |
| 1940 | Saloon Bar | Boy |
| 1940 | Just William | Ginger |
| 1940 | His Brother’s Keeper | Boy |
| 1939 | Poison Pen | Choirboy |
| 1938 | Convict 99 | Jimmy |
| 1938 | Hey! Hey! USA | Boy |
| 1938 | I See Ice | Boy on train |
| 1938 | Murder in the Family | Peter Osborne |
