He was rushed to a local trauma centre but later died from his injuries.
Three, possibly four, suspects were seen fleeing the area and have not yet been apprehended, police say.
Police believe one of the suspects had a firearm but it is not clear if the other suspects were also armed.
Police are appealing to anyone who may have been in the area at the time of the shooting to call Toronto police or Crime Stoppers if they have not already spoken to investigators.
“We know there were quite a few people out last night at 11 p.m. in the square or in the surrounding area. I would ask them if they witnessed the shooting to contact us at the Toronto police homicide squad,” Det. Stephen Henkel told CP24 at the scene.
“Businesses in the area as well, if they can review their CCTV footage for that time period or prior, again please contact us. Officers will be coming to all the businesses and canvassing for video.”
Yonge Street was closed from Dundas Street to Shuter Street but the area has since reopened to traffic.
The name of the victim has not been released.
Mayor says recent murders can’t be ‘brushed aside’
On Thursday, Mayor John Tory released a statement about the spike in homicides in Toronto, calling the violence “shocking.”
“The incidents of gun violence we have seen in our city in the past few days are shocking and can in no way be accepted or brushed aside,” the statement read.
Tory added that he spoke to Police Chief Mark Saunders this morning and has been “assured” that police are doing everything they can to apprehend those responsible.
“Police are also deploying additional resources where they believe they will be most effective. I will be following up with him and relevant City officials in the days to come to ensure that we are doing everything possible to reduce the number of these incidents and assist with law enforcement,” Tory said.
He urged anyone with information to contact investigators.
“I know we are all committed to ensuring Toronto continues to be a safe city. I encourage anyone who has information that could help solve these crimes to call police or Crime Stoppers and help us ensure we catch those who would threaten our city’s safety.”