Which player's number was the first to be retired in NHL history?

Ace Bailey was the player whose number was first retired in NHL history: the Toronto Maple Leafs retired his No. 6 on February 14, 1934.

Bailey’s career ended after a serious 1933 incident involving Boston Bruins defenseman Eddie Shore. Bailey suffered a fractured skull and never played another NHL game. A benefit game was organized for Bailey and his family at Toronto’s Maple Leaf Gardens, where Maple Leafs owner Conn Smythe announced that no Toronto player would wear No. 6 again.

That decision made Bailey’s number the first retired by an NHL team and is widely recognized as the first jersey-number retirement in professional sports. The event also helped inspire the tradition of NHL benefit and All-Star games, although the league’s official annual All-Star Game did not begin until 1947.

A common mix-up involves Howie Morenz, whose No. 7 was the first retired by the Montreal Canadiens after his death in 1937. That was important in Canadiens history, but it came several years after Toronto retired Bailey’s number.