On November 29, 2011, Ryerson University announced that Peter Gilgan, Founder and Chief Executive Officer, Mattamy Homes Ltd., contributed a donation of $15 million to the university.
In honour of Gilgan, the new athletic complex was renamed Mattamy Athletic Centre at the Gardens.
The ice rink, which is located on the third level, was named Mattamy Home Ice.

The athletic centre construction was completed in summer of 2012 and the ice rink became the new home for the Ryerson Rams hockey team.
The first game took place on September 9, 2012 with the Rams taking a 5-4  victory over the University of Ontario Institute of Technology Ridgebacks.
The arena is home to the Ryerson Rams' hockey, basketball and volleyball teams.

During the Summer of 2012, the Canadian Lacrosse League announced the relocation of the Oshawa Machine to Toronto as the Toronto Shooting Stars.
It was also announced that the team would play out of the Mattamy Athletic Centre bringing Lacrosse back to the Gardens after a 13-year absence.
The team held their first game on January 13, 2013.
The pre-game honored former Toronto Rock and Tomahawk players.
The team played one season at the arena before folding.

During the 2012–13 NHL lockout the National Hockey League Players' Association (NHLPA) used the arena for a charity game.
In addition, from January 25 to 27, 2013, the Ontario Liberals used the Gardens for their leadership convention.
The arena hosted the 2013 Players' Championship, a Capital One Grand Slam of Curling event.
The facility also hosted the 2014 OUA Figure Skating Championships, won by the Guelph Gryphons.

On December 13–14, 2014, the arena was the host of two exhibition games between the Canada men's national junior ice hockey team and a team University All Stars of combined Ryerson Rams, University of Toronto Varsity Blues and York Lions players in preparation for Canada's participation in the 2015 World Junior Ice Hockey Championships.

The arena, under the name Ryerson Athletic Centre, was one of the venues for the 2015 Pan American and Parapan American Games, hosting the basketball tournament of the 2015 Pan American Games, wheelchair basketball of the 2015 Parapan American Games and various events (Indoor rowing, powerlifting, sitting volleyball, wheelchair basketball and wheelchair rugby) for the 2017 Invictus Games.

On February 13, 2018, the arena hosted an open practice for the Maple Leafs.
This marked the first official Leafs event in the building since the last Leafs game played there in 1999 nineteen years to the day.
On November 29, 2011, Ryerson University announced that Peter Gilgan, Founder and Chief Executive Officer, Mattamy Homes Ltd., contributed a donation of $15 million to the university. In honour of Gilgan, the new athletic complex was renamed Mattamy Athletic Centre at the Gardens. The ice rink, which is located on the third level, was named Mattamy Home Ice.
The athletic centre construction was completed in summer of 2012 and the ice rink became the new home for the Ryerson Rams hockey team. The first game took place on September 9, 2012 with the Rams taking a 5-4  victory over the University of Ontario Institute of Technology Ridgebacks. The arena is home to the Ryerson Rams' hockey, basketball and volleyball teams.
During the Summer of 2012, the Canadian Lacrosse League announced the relocation of the Oshawa Machine to Toronto as the Toronto Shooting Stars. It was also announced that the team would play out of the Mattamy Athletic Centre bringing Lacrosse back to the Gardens after a 13-year absence. The team held their first game on January 13, 2013. The pre-game honored former Toronto Rock and Tomahawk players. The team played one season at the arena before folding.
During the 2012–13 NHL lockout the National Hockey League Players' Association (NHLPA) used the arena for a charity game. In addition, from January 25 to 27, 2013, the Ontario Liberals used the Gardens for their leadership convention. The arena hosted the 2013 Players' Championship, a Capital One Grand Slam of Curling event. The facility also hosted the 2014 OUA Figure Skating Championships, won by the Guelph Gryphons.
On December 13–14, 2014, the arena was the host of two exhibition games between the Canada men's national junior ice hockey team and a team University All Stars of combined Ryerson Rams, University of Toronto Varsity Blues and York Lions players in preparation for Canada's participation in the 2015 World Junior Ice Hockey Championships.
The arena, under the name Ryerson Athletic Centre, was one of the venues for the 2015 Pan American and Parapan American Games, hosting the basketball tournament of the 2015 Pan American Games, wheelchair basketball of the 2015 Parapan American Games and various events (Indoor rowing, powerlifting, sitting volleyball, wheelchair basketball and wheelchair rugby) for the 2017 Invictus Games.
On February 13, 2018, the arena hosted an open practice for the Maple Leafs. This marked the first official Leafs event in the building since the last Leafs game played there in 1999 nineteen years to the day.
Maple Leaf Gardens