Following that successful junior triumph Millar turned pro in 1941-42 with the AHA's Omaha Knights where he contributed three goals and eleven points in 50 games. Beginning the next season Millar played three years with the Winnipeg Navy team while also suiting up for several games with the Calgary Combines and Cornwallis Navy during World War Two.

Millar returned to professional action when he joined the Indianapolis Capitals for the 1945-46 season at the conclusion of the war. He remained with the club for four seasons, the best of which came in his final year in 1947-48 when he tallied 44 points in 68 games.

Millar played in just four NHL games, all with the Detroit Red Wings in 1946-47. Although he was held off the scoresheet, he had the honour of playing alongside such stars as; Ted Lindsay, Sid Abel, and an 18-year-old named Gordie Howe.

Courtesy of the Hockey Hall of Fame