Cooper Smeaton played all sports as a boy, but his affiliation with hockey began early and lasted, quite literally, until the day he died. Although he was adept at football, baseball and basketball, hockey was his game of choice, and in his early twenties, he twice rejected offers to turn professional. Instead, he turned to refereeing, starting in local amateur leagues and later, joining the National Hockey Association when league president Frank Calder appointed him an official in 1913. His first game was a contest between the two Montreal franchises, the Canadiens and Wanderers, and on the first play, Newsy Lalonde confronted him after Smeaton called an offside. The rookie referee fined the superstar five dollars, and he had established himself for all time.
In 1917, a group of fans called "Murderers Row" presented him with two trophies in appreciation for the considerable criticism he took from them during the 1916 season. They acknowledged that they, who seemingly knew it all, appreciated the fact that he, too, was conversant with at least a portion of the rules of the National Hockey Association.
Smeaton refereed the opening game of the new Montreal Forum on November 29, 1924, a contest won by the Montreal Canadiens 7-1 over the Toronto St. Patricks. The following year, he refereed the first-ever game played at Madison Square Garden in New York. That game was won by the visiting Montreal Canadiens 3-1 over the New York Americans.
He was the referee in three Stanley Cup Challenge series. He refereed all four games in the 1925-26 series between the Victoria Cougars and Montreal Maroons. He refereed all five games in the 1921-22 series between the Toronto St. Pats and the Vancouver Millionaires, as well as all five games in the 1919-20 series between the Ottawa Senators and the Seattle Metropolitans. His game total for Stanley Cup Challenge series was 14 games.
Hockey was considered a part-time position during the first many decades of the NHL, and Smeaton joined the Sun Life Association of Canada in Montreal, working his way up from clerk and cashier to branch manager and remaining with the company until he retired in 1954. He took a hiatus from hockey and Sun Life to serve in the First World War, and returned home in 1919. In 1930, stepped out of officiating to manage the Philadelphia Quakers during their single, ill-fated season in the NHL, but returned to refereeing the following season.
Cooper Smeaton was acknowledged as a fearless referee who always showed good sense. He was known for his fairness, integrity and acumen in the sports world. Jack Adams, coach and general manager of the Detroit Red Wings, named Smeaton the best referee ever to work in major league hockey. He said Cooper had the respect of all the players and managers and never let a game get out of control.
Following his retirement from officiating in 1937, Smeaton served as the NHL's Referee-in-Chief, but he resigned when the league governors failed to support one of his decisions against Eddie Shore of the Boston Bruins.
Smeaton was one of the inaugural inductees into the Hockey Hall of Fame in 1945 at a time when the institution existed in name only and not in bricks and mortar form. In 1946, Stanley Cup trustee P.D. Ross named Smeaton co-trustee to replace the recently deceased William Foran, a position every trustee holds from their nomination to the day of death. Later, when Ross passed away, Smeaton named Red Dutton co-trustee.