Major League Hockey gained its name in 2004. Since 1990, Major League Hockey was known as the Southwestern Senior "A" Hockey League. This league was created through a merger between the Central Senior "B" Hockey League, the Seaway-Cyclone Senior "B" Hockey League, and the Southern Ontario Senior "A" Hockey League. The formation of the Major League Hockey marked the first time since 1987 and the folding of the OHA Senior A Hockey League that the Ontario Hockey Association has crowned a top level senior league. In 2005, the OHA also granted the Eastern Ontario Senior Hockey League the same status. Major League Hockey, despite its fruitation in 1990, has its roots scattered across a variety of leagues dating back as far as 1959.
The first season of Ontario Hockey Association senior hockey was the 1890-91 season, for the Cosby Cup. Ottawa won the first ever Senior title defeating Toronto St. Georges 5–0. The first "Major" league came in 1929, known as the OHA Senior A Hockey League. The league lasted for fifty season, its teams winning 16 Allan Cups. The league was replaced by the Continental Senior A Hockey League in 1979. The Continental league was renamed the OHA Senior A Hockey League in 1980 and lasted until 1987. Teams of the Continental league won 4 Allan Cups.
In 2008, the Brantford Blast became the first OHA team since the Brantford Motts Clamatos in 1987 to win the Allan Cup. As hosts of the 2008 Allan Cup, the Blast failed to win their league and were allowed to bypass the OHA Final against the Whitby Dunlops and the Renwick Cup against the Thunder Bay Hawks. After almost a months rest, the Blast competed at home for the Allan Cup and won the entire thing. After suffering their only loss of the tournament to the Shawinigan Xtreme in the first game, the Blast defeated the Bentley Generals to clinch second in their division. They defeated the Robertson Cup and EOSHL champion Whitby Dunlops in the quarter-final. They then knocked off the Major League Hockey and Renwick Cup champion Dundas Real McCoys in the semi-final. They met Bentley again in the final, and defeated them 3-1 to win the Canadian National Senior "AAA" crown.
In May 2008, it was announced that Major League Hockey was going to merge with the Eastern Ontario Senior Hockey League. Major Hockey League was down to two teams and the Eastern League down to three at the time, but this brings the MLH up to five again. In June, 2008 after some reorganization, the Frankford Huskies were revived with a new owner but same management in the town of Baltimore which is just north of Cobourg. The team will be known as the Baltimore Clippers. Thus the new MLH will play its first season with six teams.
In the Summer of 2009, the Brantford Blast took a leave of absence from the MLH. The Baltimore Clippers left the league during the 2009 off season[2]
For the 2010-11 season, the Brantford Blast returned to the league; the Orillia/Coldwater Tundras abandoned Coldwater with the opening of the new Rotary Place Rink, which is part of the West Orillia Sports Complex.
The league was renamed Allan Cup Hockey for the 2011-12 season.
The 2013-14 season had the addition of the Stoney Creek Generals, the return of the Norwood Vipers and the departure of the Orillia Tundras.
The Welland Whalers withdrew on October 20, 2014 citing a lack of players stating that they had tried to invite as many players as they could to training camp but to no avail.
On May 15,2015 the league announced the addition of a team to be based in Hamilton to play out of the Dave Andreychuk Mountain Arena and a team to be based out of Thorold, Ontario to play out of the Thorold Community Arena. On June 3rd the Hamilton team announced they would be called the Steelhawks. The Steelhawks name was previously used by the city's OHL franchise from 1984 to 1988. The Thorold team has yet to release their nickname (as of July 20th).
As of the 2015 Allan Cup, the only Major League Hockey/Allan Cup Hockey teams to win the Allan Cup have been the Brantford Blast, who won it as the host team in 2008 and the Dundas Real McCoys, who won it as the host team in 2014.
On October 16, 2015 the Norwood Vipers announced they were suspending operations and not continuing in the league. In the league's press release on the Norwood team's announcement the league stated they were working to bring another team to the geographic area for the 2016-17 season.
The Thorold Athletics were not on the league schedule for the 2017-18 season when it was released on September 1, 2017.
During the summer of 2018 the owner of the Brantford Blast had announced he was putting the team up for sale and would not be running the team going forward. No one purchased the team by early September and the team announced it would suspend operations for the 2018-19 season with the hope of returning under new ownership in 2019-20. The team was sold to the owner of the Stoney Creek Generals who originally planned on operating two teams but decided to relocate the Generals to Brantford assuming the Blast name and history.
On August 9, 2020, Ian Young, the owner of the Whitby Dunlops announced they would be taking the 2020-21 season off to attempt to regroup and bring the franchise back for 2021-22.[3]
The league would decide to cancel the 2020-21 season on December 23rd, 2020 [4]
On August 9, 2020, Ian Young, the owner of the Whitby Dunlops announced they would be taking the 2020-21 season off to attempt to regroup and bring the franchise back for 2021-22.[5] They are apparently not returning for the 2021-22 season. The team website remains active but no mention of the 2021-22 season has been made.
On June 14, 2021 the league issued a release stating that it was starting a Senior AA league (tentatively called the Senior AA G-League, after the National Basketball Association's developmental G League) for players aged 21 to 28. The new league had already been approved by the Ontario Hockey Association and the Ontario Hockey Federation. The league grew out of the lost 2020-21 playing season as many 20 year olds lost their final year of junior hockey and were left with few options for competitive hockey outside of Canadian university of American collegiate leagues. The major eligibility difference with ACH will be that the new league will not permit ex-pro players. The primary focus for the league will be players from the Ontario Junior Hockey League, Greater Ontario Junior Hockey League and the Provincial Junior Hockey League (OHA).[8]
The league will also fill a void for lower level senior hockey in the Golden Horseshoe region as there is no other Senior AA level league covering the area. There are three other senior leagues in the province for 2021-22 as the Western Ontario Super Hockey League begins play being based out of southwestern Ontario, the Eastern Ontario Super Hockey League fills most of the area covered by Hockey Eastern Ontario and the area east of Greater Toronto Area, and the WOAA Senior AA Hockey League plays in the area east of Lake Huron and southwestern Ontario west of the Golden Horseshoe region.
