The pedestrian struck near Bluevale on Monday night has died of his injuries. He has been identified as 27-year-old Jordan Moorehead of Kitchener.
A post-mortem examination is scheduled to take place Wednesday in London.
Police say they have leads on the vehicle and driver that hit and killed the young man, but have not laid any charges yet.
OPP were called to the scene on Amberley Road near Ramsay Line, just east of Bluevale, around 8:30 p.m. Monday.
Upon arrival officers found an unresponsive male lying on the shoulder of the roadway. He was transported to by air ambulance to a London hospital with life-threatening injuries.
Police say Moorehead succumbed to his injuries on Tuesday afternoon.
Investigators have released a photo of a passenger-side mirror found at the collision scene that is believed to be from the suspect vehicle - possibly a heavy-duty pickup or utility truck.
Anyone with information on the vehicle or driver that may have been involved is asked to contact Huron County OPP at 1-888-310-1122 or 519-524-1074.
Moorehead described as "happy go lucky"
Moorehead's girlfriend Ashley Schell says the 27-year-old was a "kind, outgoing and fun-loving" man who lit up a room when he walked in.
The couple - along with their six-year-old daughter - moved to Wingham recently from Kitchener. It was going to be a fresh start for the pair, who both had troubled pasts.
Schell says he always told her to be positive and look on the bright side, but that will be a lot harder now.
"It shouldn't happen to anyone, but someone like him, he made a difference in many people's lives. I know he did in mine."
She believes he was likely walking home after running out of gas when he was hit by a passing vehicle just east of Bluevale.
"He would always call me and be like 'I don't have any gas, I've run out on the side of the street.' So that's what we think happened, that he ran out of gas, he parked it somewhere and started walking...He had my cellphone thank goodness and was trying to probably find some sort of wi-fi spot to get ahold of someone to try and contact them."
She says his truck was found Wednesday afternoon about eight kilometres from the spot where he was struck.