History of the National Hockey League

The history of the National Hockey League begins with the end of its predecessor league, the National Hockey Association (NHA), in 1917. After unsuccessfully attempting to resolve disputes with Eddie Livingstone, owner of the Toronto Blueshirts, executives of the three other NHA franchises suspended the NHA, and formed the National Hockey League (NHL), replacing the Livingstone team with a temporary team in Toronto, the Arenas. The NHL's first quarter-century saw the league compete against two rival major leagues—the Pacific Coast Hockey Association and Western Canada Hockey League—for players and the Stanley Cup. The NHL first expanded into the United States in 1924 with the founding of the Boston Bruins, and by 1926 consisted of ten teams in Ontario, Quebec, the Great Lakes region, and the Northeastern United States. At the same time, the NHL emerged as the only major league and the sole competitor for the Stanley Cup; in 1947, the NHL completed a deal with the Stanley Cup trustees to gain full control of the Cup. The NHL's footprint spread across Canada as Foster Hewitt's radio broadcasts were heard coast-to-coast starting in 1933.

The Great Depression and World War II reduced the league to six teams, later known as the "Original Six", by 1942. Maurice Richard became the first player to score 50 goals in a season in 1944–45, and ten years later, Richard was suspended for assaulting a linesman, leading to the Richard Riot. Gordie Howe made his debut in 1946, and retired 35 seasons later as the NHL's all-time leader in goals and points. "China Clipper" Larry Kwong becomes the first non-white player in the league, breaking the NHL colour barrier in 1948, when he played for the New York Rangers. Willie O'Ree broke the NHL's black colour barrier when he suited up for the Bruins in 1958. In 1959, Jacques Plante became the first goaltender to regularly use a mask for protection.

The Original Six era ended in 1967 when the NHL doubled in size by adding six new expansion teams. The six existing teams were formed into the newly created East Division, while the expansion teams were formed into the West Division. The NHL continued to expand, adding another six teams, to total 18 by 1974. This continued expansion was partially brought about by the NHL's attempts to compete with the World Hockey Association, which operated from 1972 until 1979 and sought to compete with the NHL for markets and players. Bobby Hull was the most famous player to defect to the rival league, signing a $2.75 million contract with the Winnipeg Jets. The NHL became involved in international play in the mid-1970s, starting with the Summit Series in 1972 which pitted the top Canadian players of the NHL against the top players in the Soviet Union, which was won by Canada with four wins, three losses, and a tie. Eventually, Soviet-Bloc players streamed into the NHL with the fall of the Iron Curtain in 1989.

When the WHA ceased operations in 1979, the NHL absorbed four of the league's teams, which brought the NHL to 21 teams, a figure that remained constant until the San Jose Sharks were added as an expansion franchise in 1991. Since then, the league has grown from 22 teams in 1992 to 32 today as the NHL spread its footprint across the United States. The league has withstood major labour conflicts in 1994–95 and 2004–05, the latter of which saw the entire 2004–05 NHL season canceled, the first time in North American history that a league has canceled an entire season in a labour dispute. Wayne Gretzky passed Gordie Howe as the NHL's all-time leading scorer in 1994 when he scored his 802nd career goal. Mario Lemieux overcame non-Hodgkin lymphoma to finish his NHL career with over 1,700 points and two Stanley Cup championships. Increased use of defence-focused systems helped cause scoring to fall in the late 1990s, leading some to argue that the NHL's talent pool had been diluted by 1990s expansion. In 1998, the NHL began awarding teams a single point for losing in overtime, hoping to reduce the number of tie games; after the 2004–05 lockout, it eliminated the tie altogether, introducing the shootout to ensure that each game has a winner.