The accident occurred on Warden Avenue about 100 metres north of Finch Avenue at 9:27 p.m.
Police said the pedestrian was heading to the east side of Warden when a northbound vehicle struck him.
"He was near the centre of the northbound lanes," Sgt. Tim Burrows said. "He wasn't crossing at an intersection. He was crossing mid-block."
The victim, whose name wasn't released, was taken by ambulance to Sunnybrook Health Sciences Centre with life-threatening injuries. He remains in the hospital's intensive care unit.
The driver wasn't hurt.
Burrows, of the traffic services unit, said police have contacted the pedestrian's family in China.
Meanwhile, police want to speak with two women who stopped to help victims of a two-car crash at Birchmount Road and McNicoll Avenue shortly after 8 a.m. Sunday.
"They left before the police could have an opportunity to talk to them," Burrows said. "We're treating them as witnesses, that they saw everything that happened. We need them to come and talk to us and tell us what they saw."
The accident occurred between an eastbound Toyota Corolla and a southbound Toyota Corolla, police said.
A passenger in the eastbound car was taken to hospital with what were initially believed to be serious injuries. The injuries turned out to be minor.
Anyone with information on either collision is asked to call traffic services at 416-808-1900.