Richard Peddie says he will retire as president and CEO of Maple Leaf Sports and Entertainment at the end of next year.
MLSE says an executive search committee has been formed to identify Peddie's successor.
The 63-year-old Peddie has been with MLSE since November 1996, helping oversee a massive amount of growth.
During that time, MLSE acquired the Toronto Raptors, opened the Air Canada Centre, established the Toronto FC MLS team and expanded its business interests with a condo and entertainment development.
MLSE chairman Larry Tanenbaum says "Maple Leaf Sports and Entertainment is what it is today due in large measure to the great team that Richard Peddie has built."