The Greater Toronto Hockey League was founded in 1911 by Frank D. Smith. In its inaugural season, it had 5 teams and 99 players. Frank Smith was 17 years old when he established this organization and continued to manage it for 50 years. In 1962, he was inducted into the Hockey Hall of Fame, notably for his contributions to youth hockey development in Toronto.

The league's name changed several times throughout its history. Initially, it was called the Beaches League, then, after its establishment, it was renamed the Toronto Hockey League (THL). In 1972, it was renamed the Metropolitan Toronto Hockey League before receiving its current name, the Greater Toronto Hockey League, in 1998. In the early years of its existence, the league saw an increase in participants. During World War I, the THL maintained its numbers by having younger age groups, such as peewee and bantam, where the players were too young to participate in the war. In the 1960s, the league had over 20,000 participants across teams all over Toronto.

In the summer of 1989, the MTHL and the Ontario Minor Hockey Association (OMHA) broke away from the Ontario Hockey Association (OHA) and formed the Central Hockey Association of Canada due to disagreements with the OHA's proposed restructuring, which would have limited their voting rights. The dispute ended when the Ontario Hockey Federation (OHF) was created with equal representation from the OHA, Northern Ontario Hockey Association, MTHL, and OMHA. The OHF was given oversight of hockey in Ontario and was a reform commission for three years to propose further restructuring if needed.