The original seven were the Bradford Rattlers, Deseronto Thunder, King Wild, Nipissing Alouettes, Richmond Hill Rams, South Muskoka Shield, and Toronto Canada Moose.

The first goal in the league's history was scored by the Rams' Darren Archibald (future Vancouver Canucks prospect) on the power play during the first period.

Rams' goaltender Daniel Jones picked up the historical first victory, as well as the league's first shutout in history.

The affiliation resulted in a national championship between the GMJHL playoff champion and the winner of the WHA Junior West Hockey League after the 2006–07 season.

In September 2007, the GMJHL started its second season with six new teams, the Douro Dukes, Elliot Lake Bobcats, Espanola Kings, Innisfil Lakers, Tamworth Cyclones, and Temiscaming Royals.

On December 11, 2007, the GMJHL announced a seven-game challenge series versus a Russian team known as the Moscow Selects.

In March 2008, the King Wild and Richmond Hill Rams played two games each against the Mexico national ice hockey team.

The GMJHL added the Minden Riverkings and the Oro-Medonte 77's to the mix, and the Dukes relocated to become the Brock Bucks.

Victorious were the Elliot Lake Bobcats (twice), South Muskoka Shield, King Wild, Bradford Rattlers, Innisfil Lakers, and a Nipissing/Ville-Marie combined squad.

First, Canada's only All-Russian team[3] in the Shelburne Red Wings and then late in the summer they expanded to the United States through the expansion of the Jamestown Jets.

In mid-January 2011, it was announced that the town of Iron Bridge, Ontario and its 500-seat outdoor arena would host a regular season game, known as the North Shore Winter Classic, between the Elliot Lake Bobcats and Algoma Avalanche on January 29, 2011.

For 2017–18, the league added the Fergus Force, Ville-Marie Pirates, Wiarton Schooners, and Windsor Aces while losing the Toronto Attack.

In late August 2017, the Parry Sound Islanders announced they were taking a leave of absence and merged with the Seguin Huskies.

The GMHL also added two teams originally in the Canadian Premier Junior Hockey League in the Niagara-on-the-Lake Nationals and Ottawa Sharpshooters for 2018–19.

The following 2020–21 season did not take place as scheduled due to pandemic restrictions in Ontario and Quebec, with six teams playing only two games each in December 2020.