Well known for his functions in various 1930s and ’40s movies, O’Neill typically played adult, dignified characters like the Duc de Choiseul in Madame Du Barry (1934) and Canon Roche in the 1946 feature The Green Years. He started his acting profession like a touring theatrical performer. Pursuing his support in World Battle I, he made an appearance in his 1st two movies: The Globe Changes and Woman Killer (both released in past due 1933). Portraying colonel and railway professional Cyrus K. Holliday, O’Neill made an appearance with Errol Flynn, Olivia de Havilland, and Ronald Reagan in the 1940 traditional western Santa Fe Path. He was raised in Orange, NJ, and later resolved in LA, California. His relationship to Anna Barry created one young child. His last screen appearance is at the 1957 John Wayne feature The Wings of Eagles.