He is best known as the principal owner of the Toronto Maple Leafs from 1927 to 1961 and as the builder of Maple Leaf Gardens. He has his name on the Stanley Cup 11 times.

From "Legends of Hockey":

Conn Smythe’s name was synonymous with hockey in Toronto for five decades. Having purchased the Toronto St. Pats in 1927, Smythe changed their name to the Toronto Maple Leafs, and altered their sweaters to the blue and white we know today. A powerful leader, Smythe had been coach, general manager and owner of the Toronto Maple Leafs before he was recognized by the Hockey Hall of Fame with his induction as a builder in 1958. It was around this time that Conn Smythe sold controlling interest in Maple Leaf Gardens to his son Stafford, Harold Ballard and John Bassett. In 1964, Maple Leaf Gardens donated a trophy for presentation to the most valuable player in each season’s playoff competition.