He played for the Boston Bruins and Toronto Maple Leafs after a long senior-hockey career, winning the Allan Cup in 1948.
He played two and a half seasons with the Bruins before being claimed on waivers, for $15,000 on January 7, 1959, by the Toronto Maple Leafs.
He was named to coach the Etobicoke Indians of the Ontario Hockey Association in 1966, but left the position to join Jack Kent Cooke, owner of the expansion Los Angeles Kings, as head scout, and later Regan was promoted to general manager.
An investigation by a Boston-area reporter named Russ Conway led to Alan Eagleson being indicted and convicted on fraud and was sentenced to prison.
Regan was head of the NHLAA at the time and he participated in the investigation, contacting any player involved with Eagleson.
Regan retired soon after the Eagleson inquiry and he lived in Ottawa, Ontario with his wife Pauline until his death in 2009.