Major League Hockey gained its name in 2003. 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.
In the 2008 off-season, Major League Hockey ran into some issues. The Windsor St. Clair Saints, the league's only college team, walked away from the league. The Tillsonburg Vipers have officially left the league, as they have applied for expansion into the independent Western Ontario Athletic Association Senior Hockey League.The Petrolia Squires are stranded far away from Brantford and Dundas and have also been accepted into the Western Ontario Athletic Association Senior Hockey League. In the EOSHL, the Frankford Huskies and Marmora Lakers have walked away as well.
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 2011, the league changed its name to Allan Cup Hockey