History of the National Hockey League/1942–1967/World War II and after

Syl Apps, with the Cup before it was redesigned, in the 1940s

Red Dutton briefly served as NHL president between 1943 and 1946.

Clarence Campbell served as the NHL's third President from 1946 until his retirement in 1977.

In February 1943, league President Frank Calder collapsed during a meeting, dying shortly after. Red Dutton agreed to take over as president after receiving assurances from the league that the Brooklyn franchise he had operated would resume play after the war. When the other team owners reneged on this promise in 1946, Dutton resigned as league president. With Dutton's recommendation, Clarence Campbell was named president of the NHL in 1946. He remained in that role until his retirement in 1977. Campbell's tenure matched the stability of the league. For the first 21 years of his presidency, the same six teams competed for the Stanley Cup and that period has been called the "golden age of hockey". The NHL featured increasingly intense rivalries coupled with rule innovations that opened up the game.

World War II had ravaged the rosters of many teams to such an extent that by the 1943–44 season, teams were battling each other for players. In need of a goaltender, The Bruins won a fight with the Canadiens over the services of Bert Gardiner. Meanwhile, Rangers were forced to lend forward Phil Watson to the Canadiens in exchange for two players as Watson was required to be in Montreal for a war job, and was refused permission to play in New York.

With only five returning players from the previous season, Rangers general manager Lester Patrick suggested suspending his team's play for the duration of the war. Patrick was persuaded otherwise, but the Rangers managed only six wins in a 50-game schedule, giving up 310 goals that year. The Rangers were so desperate for players that 42-year old coach Frank Boucher made a brief comeback, recording four goals and ten assists in 15 games. The Canadiens, on the other hand, dominated the league that season, finishing with a 38–5–7 record; five losses remains a league record for the fewest in one season while the Canadiens did not lose a game on home ice. Their 1944 Stanley Cup victory was the team's first in 14 seasons. The Canadiens again dominated in 1944–45, finishing with a 38–8–4 record. They were beat in the playoffs by the underdog Maple Leafs, who went on to win the Cup.

NHL teams had exclusively competed for the Stanley Cup following the 1926 demise of the Western Hockey League. Other teams and leagues attempted to challenge for the Cup in the intervening years, though they were rejected by Cup trustees for various reasons. In 1947, the NHL reached an agreement with trustees P. D. Ross and Cooper Smeaton to grant control of the Cup to the National Hockey League (NHL), allowing the league to reject challenges from other leagues. The last such challenge came from the Cleveland Barons of the American Hockey League in 1953, but was rejected as the AHL was not considered of equivalent calibre to the NHL, one of the conditions of the NHL's deal with trustees.

The Hockey Hall of Fame was established in 1943 under the leadership of James T. Sutherland, a former President of the Canadian Amateur Hockey Association (CAHA). The Hall of Fame was established as a joint venture between the NHL and the CAHA in Kingston, Ontario, considered by Sutherland to be the birthplace of hockey. Originally called the "International Hockey Hall of Fame", its mandate was to honour great hockey players and to raise funds for a permanent location. The first eleven honoured members were inducted on April 30, 1945. It was not until 1961 that the Hockey Hall of Fame established a permanent home at Exhibition Place in Toronto.

The first official All-Star Game took place at Maple Leaf Gardens in Toronto on October 13, 1947 to raise money for the newly created NHL Pension Society. The NHL All-Stars defeated the Toronto Maple Leafs 4–3 and raised C$25,000 for the pension fund. The All-Star Game has since become an annual tradition.