Shortly before 9 a.m. on Thursday, Toronto police were called to a Francine Drive home in a residential neighbourhood near Leslie Street and Steeles Avenue East.
Const. Wendy Drummond tweeted that a man in his 60s was found with life-threatening injuries and taken to a local trauma centre.
The man later died.
Homicide detectives are now investigating.
After police arrived in the neighbourhood on Thursday, A.Y. Jackson Secondary School was put under a hold and secure, which is when the exterior doors are locked and students are restricted from leaving the school. That order has since ended.