Cowley played junior ice hockey in the National Capital Region. He was selected by Cecil Duncan to be on an Ottawa All-stars team which of played an exhibition series in Europe during December 1931 and January 1932. After a few seasons of senior league play in Ottawa and Halifax, Cowley broke in as a rookie with the St. Louis Eagles in 1934–35. After the season, the franchise was terminated and Art Ross, the general manager of the Bruins, selected him in the subsequent dispersal draft. In Boston he would become a star, leading the league in assists in 1939, 1941 and 1943, and helping to lead the Bruins to two Stanley Cups in 1939 and 1941. While World War II ravaged the Bruins' powerful roster thereafter—Boston would not win another Cup during his career—Cowley was the team's sole remaining star. Frequently injured, he was on track to shatter the league record for scoring in 1944 when another injury ended his season two points short. Nevertheless, Cowley did score four goals in a game on March 4, 1944, in a wild 10–9 Boston victory over the New York Rangers. Cowley finished his career with 195 goals and 353 assists for 548 points in 549 NHL games. On April 5, 1947, at the Bruins annual breakup party, Cowley unexpectedly announced he was leaving hockey because general manager Art Ross had chosen to leave him off of the roster for a post-season exhibition tour of western Canada and the United States. Cowley's wife was from Vancouver and he wanted to use the trip as a honeymoon. At the time of his retirement, he was the NHL's all-time leading point scorer, and the last active player from the St. Louis Eagles roster. He was inducted into the Hockey Hall of Fame in 1968, as the sole inductee into the Players category that year. In 1998, he was ranked number 53 on The Hockey News' list of the 100 Greatest Hockey Players. After his career, Cowley went on to coach in the Ottawa senior leagues and the Vancouver Canucks of the PCHL.
Personal
Returning to Ottawa after his coaching days, Cowley went into business, owning a hotel in Smiths Falls, Ontario and the Elmdale Tavern/Hotel in Ottawa. In 1967, he was a part-owner and founder of the Ottawa 67's junior ice hockey team. He passed on the Elmdale to his son John. Cowley died on New Year's Eve, 1993, of a heart attack. He was survived by his wife Jessie, children Jill Fullerton, John, Jane Egan and Dan. He is buried in the hamlet of Norway Bay, Quebec, just south-east of his birthplace of Bristol, where he had a home and spent much of his retirement years.
