[5] The Stanley Cup, the oldest professional sports trophy in North America,[6] is awarded annually to the league playoff champion at the end of each season.

Following the conclusion of the regular season, 16 teams advance to the Stanley Cup playoffs, a four-round tournament that runs into June to determine the league champion.

Toronto won the first NHL title, and then defeated the Vancouver Millionaires of the Pacific Coast Hockey Association (PCHA) for the 1918 Stanley Cup.

[19] The Canadiens won the league title in 1919, but the series in the Stanley Cup Finals against the PCHA's Seattle Metropolitans was abandoned due to the Spanish Flu epidemic.

It was the last time a non-NHL team won the trophy,[23] as the Stanley Cup became the de facto NHL championship in 1926, after the WCHL ceased operation.

[29] In 1926, Native American Taffy Abel became the first non-white player in the NHL and broke the league's colour barrier by playing for the New York Rangers.

[35] For the 1942–43 season, the NHL was reduced to six teams: the Boston Bruins, the Chicago Black Hawks, the Detroit Red Wings, the Montreal Canadiens, the New York Rangers, and the Toronto Maple Leafs, a line-up, often referred to as the "Original Six", that would remain constant for the next 25 years.

The league doubled in size to 12 teams for the 1967–68 season, adding the Los Angeles Kings, the Minnesota North Stars, the Philadelphia Flyers, the Pittsburgh Penguins, the California Seals, and the St. Louis Blues.

[46] The NHL fought the WHA for players, losing 67 to the new league in its first season of 1972–73,[47] including the Chicago Black Hawks' Bobby Hull, who signed a 10-year, $2.5 million contract with the Winnipeg Jets, then the largest in hockey history.

[49] Seven years of battling for players and markets financially damaged both leagues, leading to a merger agreement in 1979 that saw the WHA cease operations while the NHL absorbed the Winnipeg Jets, the Edmonton Oilers, the Hartford Whalers, and the Quebec Nordiques.

By the turn of the century, nine more teams were added to the NHL: the San Jose Sharks, the Tampa Bay Lightning, the Ottawa Senators, the Mighty Ducks of Anaheim, the Florida Panthers, the Nashville Predators, the Atlanta Thrashers, and, in 2000, the Minnesota Wild and the Columbus Blue Jackets.

[56] On April 18, 2024, the Arizona Coyotes suspended operations and sold their hockey assets, including players and other personnel, to a new team in Salt Lake City, Utah.

[57][58] Two months after Utah's foundation, the Coyotes ceased their efforts to re-activate within the five-year window granted to do so, bringing the NHL back to 32 franchises.

The first was an April 1992 strike by the National Hockey League Players' Association, which lasted for ten days but was settled quickly with all affected games rescheduled.

[61] The league vowed to install what it dubbed "cost certainty" for its teams, but the Players' Association countered that the move was little more than a euphemism for a salary cap, which the union initially said it would not accept.

[76] From 1952 to 1955, Marguerite Norris served as president of the Detroit Red Wings, being the first female NHL executive and the first woman to have her name engraved on the Stanley Cup.

Compared with 2022, the Maple Leafs surpassed the Rangers as the most valuable NHL team, and Los Angeles overtook both Chicago and Boston, making its way into the top five.

[89] A committee led by Bettman and chairman Jeremy Jacobs is responsible for vetting new ownership applications, collective bargaining, and league expansion.

Other members include Mark Chipman, N. Murray Edwards, Craig Leipold, Ted Leonsis, Geoff Molson, Henry Samueli, Larry Tanenbaum, Jeff Vinik, and David Blitzer.

Since 2005, when a team is guilty of icing the puck they are not allowed to make a line change or skater substitution of any sort before the following face-off (except to replace an injured player or re-install a pulled goaltender).

The Stanley Cup playoffs, which go from April to the beginning of June, are an elimination tournament where two teams play against each other to win a best-of-seven series in order to advance to the next round.

Players cannot enter until three years have passed since their last professional game, currently tied with the Naismith Memorial Basketball Hall of Fame[121] for the shortest such time period of any major sport.

One unique consequence has been Hall of Fame members (specifically, Gordie Howe, Guy Lafleur, and Mario Lemieux) coming out of retirement to play once more.

The table follows the Hockey Hall of Fame convention of classifying players by the currently existing countries in which their birthplaces are located, without regard to their citizenship or where they were trained.

[137] Likewise, Tim Hortons is the league's official coffee and doughnuts chain in Canada, while Dunkin' Donuts is the NHL's sponsor in the United States.

The winning community gets a cash prize dedicated to upgrading their local home arena, as well as the opportunity to host an NHL pre-season game.

Hockey broadcasting on a national scale was particularly spotty prior to 1981; NBC, CBS, and ABC held rights at various times during that period but with limited schedules during the second half of the regular season and the playoffs, along with some (but not all) of the Stanley Cup Finals.

The most recent IIHF-organized event including an NHL club was the 2009 Victoria Cup, between the Swiss National League A's ZSC Lions and the Chicago Blackhawks.

The debut of the Winter Classic, an outdoor regular season NHL game held on New Year's Day in 2008, was a significant success for the league.

The 2010 Stanley Cup playoffs saw the largest audience in the sport's history "after a regular season that saw record-breaking business success, propelled largely by the NHL's strategy of engaging fans through big events and robust digital offerings.