Firefighters responded to the fire — which was contained to a single, sixth-floor unit — just before 5 a.m.
Fire crews quickly extinguished the flames but found a man lying three metres from the front door without vital signs and suffering from third-degree burns.
Shane Straiko lives a few doors down from the unit that caught fire. He and his girlfriend could smell smoke and when they opened their door they realized there was a fire. They ran to see if they could help.
"I pounded on the door. There was no response," he said. "The doors were too heavy to try to break down. We couldn't get into the room. There was nothing we could do."
Two smoke alarms were found in the loft apartment, but it's not known whether they were working, said Mike Strapko, captain of Toronto Fire Services.
"We're not sure where the victim was initially when the fire started, but he had seemingly been trying to make his way towards the door," Fire Services division commander Bob O'Hallaran said.
The Fire Marshal's Office said the blaze started in the living room. The fire was contained, but the unit is gutted. There is water damage to several units as well as the hallway.
The cause of the fire has not been determined.