He played junior and senior hockey in Saskatoon with the Saskatoon Wesleys and the Saskatoon Crescents from 1930 to 1932. In 1932 he turned pro with the Boston Cubs. From 1933-34 to 1936-37 he was a regular with the Boston Bruins. O'Neil played in the American Hockey League from 1936 until his retirement. He had two brief stints with the Montreal Canadiens in 1940-41 and 1941-42. In his NHL career O'Neil played in 156 games and scored 6 goals and 30 assists.