Which NHL team was the first to win the Stanley Cup after the league's founding?

The Toronto Arenas were the first NHL team to win the Stanley Cup after the league was founded. They won the 1918 Stanley Cup, defeating the Vancouver Millionaires three games to two in the best-of-five Final.

The championship came during the NHL’s inaugural 1917–18 season. Toronto’s franchise was created amid a dispute involving the National Hockey Association and Toronto Blueshirts owner Eddie Livingstone. Because of the unusual circumstances, the team was sometimes called the Torontos or Blue Shirts, and “Toronto Arenas” became the commonly used historical name.

The victory is connected to the modern Toronto Maple Leafs, but the franchise history is complicated. The temporary Toronto team operated by the Arena Company later became the Toronto St. Patricks and eventually the Maple Leafs. Toronto’s 1918 championship was also the first major professional sports title won by a team based in the city. The team did not originally engrave its name on the Cup; “1918 Toronto Arenas” was added to a redesigned Cup collar in 1948.