Irish-Born stage and screen performer, he had his screen debut in "The Prisoner of Zenda." (1913) He is most fondly remembered as the brilliant 'Dr. Zarkov' in the three "Flash Gordon" serials.
| Movie | Spaceship to the Unknown | Dr. Hans Zarkov (archive footage) | 1966-01-01 |
| Movie | Purple Death from Outer Space | Dr. Zarkov | 1966-01-01 |
| Movie | A Dangerous Profession | 1949-12-10 | |
| Movie | Crack-Up | Train Station Gateman (Uncredited) | 1946-09-06 |
| Movie | Batman | Dr. Hayden | 1943-07-16 |
| Movie | The Phantom | Prof. Davidson (uncredited) | 1943-12-24 |
| Movie | Ten Gentlemen from West Point | Senator (uncredited) | 1942-06-26 |
| Movie | The Secret Code | Police Commissioner | 1942-09-04 |
| Movie | Federal Fugitives | Hammond | 1941-03-29 |
| Movie | Rawhide Rangers | McDowell | 1941-07-18 |
| Movie | Flash Gordon Conquers the Universe | Dr. Zarkov | 1940-03-03 |
| Movie | Emergency Squad | Construction Supervisor at Elevator | 1940-01-05 |
| Movie | The Return of Frank James | Sheriff | 1940-08-10 |
| Movie | Wildcat Bus | Sweeney | 1940-08-23 |
| Movie | A Dispatch from Reuters | Mr. O'Malley - Captain of the Nova Scotian (uncredited) | 1940-10-19 |
| Movie | Brigham Young | Second Man with California Gold News | 1940-09-27 |
| Movie | Union Pacific | Old Man (uncredited) | 1939-05-05 |
| Movie | Torchy Blane in Chinatown | Police Capt. McTavish | 1939-02-02 |
| Movie | Torchy Runs for Mayor | Captain McTavish | 1939-05-13 |
| Movie | Torchy Blane... Playing with Dynamite | Inspector McTavish | 1939-08-12 |
| Movie | The Night of Nights | Frank, the Bartender (uncredited) | 1939-12-01 |
| Movie | Rulers of the Sea | Kelsey (Uncredited) | 1939-11-08 |
| Movie | Flash Gordon's Trip to Mars | Dr. Zarkov | 1938-03-21 |
| Movie | Rocket Ship | Dr. Hans Zarkov | 1938-03-05 |
| Movie | Mannequin | Police Sergeant at Jail (Uncredited) | 1938-01-21 |
| Movie | Blondes at Work | Capt. McTavish | 1938-02-05 |
| Movie | The Ship That Died | Minor Role (uncredited) | 1938-02-19 |
| Movie | Over the Wall | Duke Slattery - Policeman with Warrant | 1938-04-02 |
| Movie | Torchy Blane in Panama | Captain McTavish | 1938-05-07 |
| Movie | Torchy Gets Her Man | Police Captain McTavish (uncredited) | 1938-11-12 |
| Movie | Next Time I Marry | Police Lieutenant (uncredited) | 1938-12-09 |
| Movie | You Can't Take It with You | Mac (uncredited) | 1938-09-01 |
| Movie | Mars Attacks the World | Dr. Alexis Zarkov | 1938-11-07 |
| Movie | Ever Since Eve | Desk Sergeant (uncredited) | 1937-07-15 |
| Movie | The Adventurous Blonde | Captain McTavish | 1937-11-13 |
| Movie | The Perfect Set-Up | Detective Hewitt (uncredited) | 1936-02-01 |
| Movie | The Murder of Dr. Harrigan | Police Sergeant | 1936-01-11 |
| Movie | The Prisoner of Shark Island | Mr. Holt | 1936-02-28 |
| Movie | Black Gold | Dan O'Reilly | 1936-01-19 |
| Movie | Road Gang | Chaplain (uncredited) | 1936-03-28 |
| Movie | End of the Trail | Sheriff Anderson | 1936-10-10 |
| Movie | The Texas Rangers | Captain Stafford | 1936-08-28 |
| Movie | Flash Gordon | Dr. Hans Zarkov | 1936-04-06 |
| Movie | Men Without Names | Agent Joe | 1935-06-29 |
| Movie | 'G' Men | Police Chief at Lodge (uncredited) | 1935-05-04 |
| Movie | The Pace That Kills | Mr. Farley | 1935-12-01 |
| Movie | The Eagle's Brood | Mike | 1935-10-25 |
| Movie | Woman in the Dark | Prison Warden | 1934-11-08 |
| Movie | A Burglar to the Rescue | The Burglar, Holtz aka Jack Dunning | 1931-09-07 |
| Movie | Icebound | Judge Bradford | 1924-03-02 |
| Movie | Monsieur Beaucaire | Badger | 1924-08-11 |
| Movie | The Bride's Play | Sir John Mansfield | 1922-01-22 |
| Movie | Boomerang Bill | Terrence O'Malley | 1922-01-15 |
| Movie | Perjury | Phil Rourke | 1921-08-14 |
| Movie | The Prisoner of Zenda | Detchard | 1913-02-18 |