After a nine year absence, Indycars returned to the Toronto area for the Molson Diamond Indy at Mosport Park won by A.J. Foyt in 1977 and Danny Ongais in 1978.
In the spring of 1985 Molson Breweries in-house promotional division, Molstar Sports & Entertainment proposed to run a CART sanctioned IndyCar race at Exhibition Place in Toronto. Toronto City Council approved the race by two votes in July 1985 for the race to be held the following year. 
The first Molson Indy Toronto was won by Bobby Rahal on July 20, 1986. The event quickly became Canada's second largest annual sporting event, eclipsed only by the Canadian Grand Prix in Montreal, with three-day attendance figures routinely around 170,000 people.
In the 1996 race, American driver Jeff Krosnoff was killed in a crash with 4 laps remaining. In that same crash, volunteer corner marshall Gary Avrin was killed, and marshall Barbara Johnston also received injuries in the crash; she was treated and released that evening. Adrián Fernández won the race.
The name of the race was changed in 2006 from the Molson Indy Toronto to the Molson Grand Prix of Toronto after it was purchased by the Champ Car World Series from Molstar Sports and Entertainment. The name was also changed to distance Champ Car from the rival Indy Racing League (IRL), which had gained the exclusive right to use the "Indy" name after 2002. In 2007, after Molson dropped their title sponsorship to the race, Steelback Brewery signed a multi-year, multi-million dollar deal to become the event’s title sponsor, renaming it the Steelback Grand Prix of Toronto. This marked the first title sponsorship change since the event started in 1986.
The unification of Champ Car and the Indy Racing League was announced on February 22, 2008, and the Grand Prix of Toronto's future was left in doubt. After attempts were made to preserve the race for 2008, it was confirmed on March 5, 2008 that the race had been cancelled.
Looking towards the Direct Energy Centre during the 2013 race. Team Penske pits are at the bottom of the image.
On May 15, 2008, Andretti Green Racing (co-owned by Michael Andretti) purchased the assets of the former Grand Prix of Toronto. On July 30, 2008, it was confirmed that the race would return to Toronto on July 12, 2009. On September 18, 2008, Andretti Green Racing announced that it had signed a multi-year agreement with Honda Canada Inc. for the title sponsorship of the race, henceforth named from 2009 onward as the Honda Indy Toronto.
1996: Race ended with 1 1/2 laps remaining (93 of 95 laps completed) because of fatal crash on Lake Shore Boulevard. Driver Jeff Krosnoff and a track marshal were killed and the race was stopped near the impact point a lap later.