Anselmi added the title of MLSE president when he succeeded Richard Peddie on Sept. 4, 2012, but relinquished that title when Tim Leiweke arrived in April 2013 and was named president and chief executive officer.
"I am from this community and I'm a huge fan of our teams, so being part of the growth of this organization into one that is admired in the industry has been a real privilege," Anselmi, whose last day with the company will be Sept. 13, said in a statement released by MLSE. "I'm very proud of our people and all that we've been able to accomplish.
"I'm also excited about the next chapter of my career."
Toronto-based MLSE owns the NHL's Maple Leafs, NBA's Raptors, Toronto FC and the American Hockey League's Marlies.
Anselmi previously served as executive vice president of MLSE and first joined the organization in December 1996. He was responsible for the overall development of the Air Canada Centre and was appointed COO in 2004.
Anselmi's departure is the latest in a series of major changes at MLSE since Leiweke took over June 30.
Earlier this summer, the company parted ways with Toronto Raptors boss Bryan Colangelo and this week Toronto FC president and general manager Kevin Payne was fired.