Denis O'Dea was an Irish stage and film actor.
He was born in Dublin. When very young he and his mother Kathleen moved in with her sister, who kept a boarding house at 54 South Richmond Street. He worked in insurance until taking up acting. O'Dea was a leading member of Dublin's Abbey Theatre, where his work led to a number of notable film roles, including two mid-1930s John Ford films, The Informer and The Plough and the Stars, and the part of the police inspector in pursuit of IRA man James Mason in Carol Reed's Odd Man Out.
Other films in which he appeared include: The Mark of Cain, The Fallen Idol, Alfred Hitchcock's Under Capricorn, The Bad Lord Byron, Landfall, Disney's Treasure Island, Marry Me!, Captain Horatio Hornblower R.N., The Long Dark Hall, Mogambo, Niagara, Never Take No For An Answer, The Rising of the Moon, Captain Lightfoot, Darby O'Gill and the Little People and Esther and the King.