Prior to 1904, playing for pay was not favored by major hockey circuits, as they were established as purely amateur organizations.
The earliest known instance of hockey players playing publicly for pay occurred in Pittsburgh, Pennsylvania when a 1902 investigation by the Ontario Hockey Association (OHA) revealed that players on Pittsburgh-based teams received payment in 1901[11] and 1902, [12][13] leading the OHA to ban any club from Pittsburgh from participating in their association, claiming there was "ample and undeniable proof" that clubs in Pittsburgh were "purely professional, paying straight salaries to their players.
The competition for players increased salaries, a factor in the demise of the IPHL in 1907 and the temporary end of professional hockey in the United States.
While the leagues competed for players, competition for the Stanley Cup brought them together for annual playoffs, starting in 1915.
In the west, the Western Canada Hockey League was formed in 1921 from existing teams in Alberta and Saskatchewan.
The annual Stanley Cup playoffs now became a three-way championship, alternating in location between the west and the east.
The NHL, having expanded to the U.S.A. and now with ten teams, bought out the players' contracts of the WHL and took control of the Stanley Cup, forming Canadian and American divisions; it also brought in one WHL team, the Victoria Cougars, and relocated it to the U.S. to eventually become the modern Detroit Red Wings.
In the 1950s, with the rise of NHL television broadcasts, such as those on Hockey Night in Canada, attendance suffered and the minor professional leagues folded or merged to survive.
A new Western Hockey League was formed on the west coast with teams in several cities including Vancouver.
Since the demise of the QHL, the American Hockey League (AHL) has had Canadian teams, starting with the Quebec Aces.
In 1972, the World Hockey Association was formed with professional teams in Edmonton, Ottawa, Quebec City and Winnipeg.
On February 16, 2005, the NHL became the first major professional team sport in North America to cancel an entire season because of a labor dispute.
Throughout the history of the Soviet league, Red Army-affiliated CSKA Moscow dominated, winning 32 of the 46 championship seasons.
The Soviet League's talent level was severely diminished following the fall of communism when most elite players moved to the NHL in search of higher pay.
In Switzerland, the Nationalliga A (German), or Ligue Nationale A (French), or Lega Nazionale A (Italian) is the top tier of the Nationalliga or Ligue Nationale or Lega Nazionale, the main professional ice hockey league in Switzerland.
However, because of the disruption of World War II and a lack of suitable venues afterwards the sport faded rapidly.
As of 2012, the ten-team, two-division professional Elite Ice Hockey League is the highest level of competition in the United Kingdom and features teams from each of the four Home Nations.
The United States would continue to see professional hockey with teams from the PCHL, beginning with the Portland Rosebuds, followed by a Seattle-based franchise a year later.
The NHL reached a higher peak when the Seattle Kraken joined the league in 2021-22 as the 25th American team.
Teams from North American and Europe do not regularly compete against each other in "friendlies" as do soccer clubs, although efforts to expand intercontinental play have increased since the new 2000 millennium.
The opportunities for fans and media to compare levels of play between the continents were especially limited during the Cold War since many of Europe’s best clubs were behind the Iron Curtain.
After the success of the Summit Series which featured the Canadian and Soviet national teams, there was a demand for more international hockey at the club level.
This led to the Super Series which from 1975 to 1991 featured an annual tour of North America by a Soviet hockey club.
The first Super Series featured CSKA Moscow against the Montreal Canadiens on New Year’s Eve 1975, in what was described in the press as a de facto world championship.
The following week CSKA played and lost to the two-time defending Stanley Cup champion Philadelphia Flyers in a game infamous for its roughness.
Subsequent Super Series produced more close results, but generally favoured the Soviet sides.
However, following the fall of communism, many elite players from the Soviet Union and Eastern Bloc countries went to the NHL for higher pay.
In 2008, the former Russian Super League was refounded as the Kontinental Hockey League, expanded into Belarus, Latvia, and Kazakhstan, and encouraged its clubs to aggressively seek talented players (sometimes at the expense of the NHL), prompting the media to speculate about eventual KHL challenge to the NHL dominance of international hockey.
In North America, professional women's hockey developed much later than in the men's game, and has seen starts and stops.
[31][32] However, hundreds of prominent women's players, including Canadian and American Olympians, founded the Professional Women's Hockey Players' Association and opted to boycott existing leagues in pursuit of a unified, financially stable professional league.