| Movie | 1964 | Fail Safe | Brig. Gen. Warren A. Black | |
| Movie | 1982 | Halloween III: Season of the Witch | Conal Cochran | |
| Movie | 1987 | RoboCop | The Old Man | |
| Movie | 1990 | RoboCop 2 | The Old Man | |
| Movie | 1954 | The Black Shield of Falworth | Prince Hal of Wales | |
| Movie | 1984 | The Last Starfighter | Grig | |
| Movie | 1951 | The Desert Fox: The Story of Rommel | Commando Captain (uncredited) | |
| Movie | 1948 | Larceny | Duke | |
| Movie | 1959 | Imitation of Life | David Edwards | |
| Movie | 1979 | Mark Twain: Beneath the Laughter | Mark Twain | |
| Movie | 1948 | Macbeth | Macduff | |
| Movie | 1961 | King of the Roaring 20's – The Story of Arnold Rothstein | Detective Phil Butler | |
| Movie | 1969 | 100 Rifles | Steven Grimes | |
| Movie | 1955 | The Virgin Queen | Lord Derry | |
| Movie | 1947 | Odd Man Out | Nolan | |
| Movie | 1952 | Invasion, U.S.A. | Mr. Ohman | |
| Movie | 1959 | The Young Land | Judge Millard Isham | |
| Movie | 1987 | The Dead | Mr. Browne | |
| Movie | 1974 | The Tamarind Seed | Fergus Stephenson | |
| Movie | 1969 | The Big Cube | Charles Winthrop | |
| Movie | 1972 | The Carey Treatment | J.D. Randall | |
| Movie | 1993 | Love, Cheat & Steal | Hamilton Fisk | |
| Movie | 1954 | Robinson Crusoe | Robinson Crusoe | |
| Movie | 1957 | That Woman Opposite | Dermot Kinross | |
| Movie | 1952 | Actors and Sin | Alfred O'Shea / Narrator (segment Actor's Blood) | |
| Movie | 1958 | Home Before Dark | Arnold Bronn | |
| Movie | 1948 | Kidnapped | Alan Breck | |
| Movie | 1962 | The Cabinet of Caligari | Caligari / Paul | |
| Movie | 1955 | The Purple Mask | Brisquet | |
| Movie | 2020 | 'Fail-Safe' and the Cold War | Self (archive footage) | |
| Movie | 1951 | The Blue Veil | Hugh Williams | |
| Movie | 1952 | At Sword's Point | Aramis Jr. | |
| Movie | 1960 | One Foot in Hell | Sir Harry Ivers | |
| Movie | 1960 | A Terrible Beauty | Don McGinnis | |
| Movie | 1954 | Bengal Brigade | Capt. Ronald Blaine (as Daniel O'Herlihy) | |
| Movie | 1977 | MacArthur | President Roosevelt | |
| Movie | 1976 | The Quest: The Longest Drive | Mathew Hatcher | |
| Movie | 1952 | Operation Secret | Lt. Duncan | |
| Movie | 1974 | Jennie: Lady Randolph Churchill | Leonard Jerome | |
| Movie | 1970 | Waterloo | Marshal Michel Ney | |
| Movie | 1977 | Deadly Game | Colonel Edward Stryker | |
| Movie | 1951 | Soldiers Three | Sgt.Murphy | |
| Movie | 1972 | The People | Sol Diemus | |
| Movie | 1986 | The Whoopee Boys | Judge Sternhill | |
| Movie | 1988 | A Waltz Through the Hills | Uncle Tom | |
| Movie | 1981 | Death Ray 2000 | The Director | |
| Movie | 1977 | Good Against Evil | Father Kemschler | |
| Movie | 1986 | Dark Mansions | Alexander Drake | |
| Movie | 1950 | The Iroquois Trail | Lt. Blakely | |
| Movie | 1981 | Artemis '81 | Albrecht Von Drachenfels | |
| Movie | 1947 | Hungry Hill | Harry Brodrick | |
| Movie | 1953 | Sword of Venus | Danglars | |
| Movie | 1955 | Hunters of the Deep | Narrator | |
| Movie | 1998 | The Rat Pack | Joe Kennedy | |
| Movie | 2000 | Revisiting 'Fail-Safe' | Self | |
| Movie | 1976 | Banjo Hackett: Roamin' Free | Tip Conaker | |
| Movie | 1951 | The Highwayman | | |
| Movie | 2000 | Buñuel in Hollywood | Self | |
| Movie | 1957 | The Blackwell Story | Dr. Keller | |
| Movie | 1968 | How to Steal the World | Prof. David Garrow | |
| TV Show | 1984 | Murder, She Wrote | Alexander Preston | 1 |
| TV Show | 1986 | L.A. Law | Vernon Kepler | 1 |
| TV Show | 1972 | Colditz | Lt. Col. Max Dodd | 4 |
| TV Show | 1982 | Remington Steele | Charles Wellington | 1 |
| TV Show | 1979 | Trapper John, M.D. | | 1 |
| TV Show | 1976 | The Bionic Woman | | 1 |
| TV Show | 1968 | Hawaii Five-O | Harry Wells | 1 |
| TV Show | 1990 | Twin Peaks | Andrew Packard | 6 |
| TV Show | 1995 | VR.5 | Dr. Alloysius Hunnicutt | 1 |
| TV Show | 1960 | Route 66 | | 1 |
| TV Show | 1963 | The Travels of Jaimie McPheeters | Dr. Sardius McPheeters | 26 |
| TV Show | 1976 | Charlie's Angels | Freddie Brander | 1 |
| TV Show | 1977 | The Hardy Boys / Nancy Drew Mysteries | | 1 |
| TV Show | 1979 | A Man Called Sloane | | 12 |
| TV Show | 1985 | The Equalizer | Randall Payne | 1 |
| TV Show | 1962 | Combat! | Maj. Richter | 1 |
| TV Show | 1953 | General Electric Theater | | 2 |
| TV Show | 1985 | The Ray Bradbury Theater | Charles Braling | 1 |
| TV Show | 1965 | The Long, Hot Summer | | 26 |
| TV Show | 1961 | Target: The Corruptors! | | 1 |
| TV Show | 1959 | Rawhide | John Cord | 1 |
| TV Show | 1967 | The High Chaparral | Jake Lanier | 1 |
| TV Show | 1950 | Lux Video Theatre | Alan | 1 |
| TV Show | 1951 | Schlitz Playhouse of Stars | | 2 |
| TV Show | 1954 | Climax! | Ian Hamilton | 1 |
| TV Show | 1963 | Bob Hope Presents the Chrysler Theatre | | 1 |
| TV Show | 1965 | The Big Valley | David Wyncop | 1 |
| TV Show | 1959 | Adventures in Paradise | Colonel Tomlinson | 1 |
| TV Show | 1964 | Profiles in Courage | Professor Richard T. Ely | 1 |
| TV Show | 1961 | Ben Casey | | 1 |
| TV Show | 1952 | Cavalcade of America | Nathaniel Hawthorne | 1 |
| TV Show | 1956 | Dick Powell's Zane Grey Theatre | Capt. Cleve Scott | 1 |
| TV Show | 1961 | Dr. Kildare | Mark Addison | 1 |
| TV Show | 1953 | The Oscars | Self | 1 |
| TV Show | 1961 | The Defenders | Governor William Defoe | 1 |
| TV Show | 1959 | The DuPont Show with June Allyson | David | 1 |
| TV Show | 1976 | Gibbsville | | 1 |
| TV Show | 1974 | Jennie: Lady Randolph Churchill | Leonard Jerome | 1 |
| TV Show | 1953 | Letter to Loretta | Dave Hardy | 1 |
| TV Show | 1992 | Batman: The Animated Series | Grant Walker (voice) | 1 |
| TV Show | 1961 | Dr. Kildare | John Patrick McHenry | 1 |
| TV Show | 1961 | Dr. Kildare | Dr. Phillip Downey | 1 |
| TV Show | 1961 | Dr. Kildare | Mark Sloan | 1 |
| TV Show | 1950 | Lux Video Theatre | Oliver Bradford | 1 |
| TV Show | 1953 | General Electric Theater | Dr. Paul Crowley | 1 |
| TV Show | 1966 | Mission: Impossible | Jack Cole | 1 |
| TV Show | 1953 | General Electric Theater | Robert Burns | 1 |
| TV Show | 1950 | Lux Video Theatre | Henry | 1 |
| TV Show | 1952 | Cavalcade of America | Benedict Arnold | 1 |
| TV Show | 1950 | Lux Video Theatre | Trevelyan | 1 |
| TV Show | 1960 | Checkmate | Stephen Jordan | 1 |
| TV Show | 1955 | Screen Director's Playhouse | Dr. Donald Kent | 1 |
| TV Show | 1961 | The Americans | Colonel Fry | 1 |
| TV Show | 1974 | QB VII | David Shawcross | 2 |
| TV Show | 1967 | Ironside | Arthur Justin | 1 |
| TV Show | 1962 | The Alfred Hitchcock Hour | Simon Carter | 1 |
| TV Show | 1984 | Murder, She Wrote | Denton Langley | 1 |
| TV Show | 1978 | Battlestar Galactica | Dr. Ravashol | 1 |
| TV Show | 1962 | Sam Benedict | Hart Marbury | 1 |
| TV Show | 1982 | Nancy Astor | Chiswell 'Chillie' Langhorne | 4 |
| TV Show | 1964 | The Man from U.N.C.L.E. | Marcel Rudolph | 1 |
| TV Show | 1964 | The Man from U.N.C.L.E. | Capt. Rupert Oliver Morton | 1 |
| TV Show | 1967 | Hondo | Prof. Phineas Blackstone | 1 |