Watson started his career in 1919 with the Toronto Dentals before moving to the Toronto Granites the next year. The Granites, led by Watson's unmatched stick handling and speed, won the Allan cup in both 1922 and 1923. The Allan Cup is given to the Canadian Senior Amateur champions.
As a reward for being the 1923 Allan Cup champions, the Toronto Granites were chosen to represent Canada at the 1924 Winter Olympics at Charmonix, France. It was there where Moose Watson enjoyed his greatest athletic achievement and established himself as perhaps the greatest of all Canadian Olympic hockey performers.
The first game was against Czechoslovakia. Watson and teammate Albert McCaffery were a two man wrecking crew, destroying the eastern Europeans 30-0. Watson scored 13 of the 30 goals.
The tournament also featured 20-0 win over Sweden and a 33-0 victory over Switzerland. By the end of the 1924 Winter Olympics, Canada won the gold medal by scoring 110 goals in just 5 games, and giving up only 3. Watson led the way with an unthinkable 36 goals!
When Watson returned with the gold medal draped around his neck, he was bombarded with offers from professional teams from just about everywhere. Everyone wanted the heroic Watson who was considered to be the best amateur player. The Montreal Maroons even offered a then-staggering sum of $30,000 to join their team. Watson responded to all of his countless offers by retiring.
Watson would come out of retirement but remained strictly amateur. He became a player and head coach of the 1932 Allan Cup winning Toronto Nationals.
Moose Watson died on September 11, 1957. Six years later he was forever immortalized as he was inducted into the Hockey Hall of Fame.