Officers were called to the scene on Kingston Road East, east of Salem Road, just before 7:20 p.m. ET.
The 31-year-old pedestrian, from Ajax, was struck by a red Subaru Legacy as he crossed Kingston Road southbound "against the red light," according to police.
The man was taken to hospital, where he succumbed to his injuries. The driver of the vehicle was not injured, police said.
The incident closed the road for several hours while police investigated.
Anyone with potentially helpful information about this incident is asked to call 1-888-579-1520 ext. 5231.