Officials said 26-year-old Dean Wiwchar was arrested without incident on Thursday and is expected to appear in court to face a first-degree murder charge on Friday.
Det. Sgt. Terry Browne said Wiwchar is a resident of British Columbia who has a connection to Toronto, and was carrying identification under different names.
Toronto police aren't saying much else about the case as an "extensive investigation" involving other police forces, including the RCMP, is still underway.
"Because this is an active and continuing investigation, I cannot comment on the circumstances that led to his arrest," said Browne, adding that Wiwchar was not known to Toronto police.
"This is the very very beginning of that investigation, there is a lot of leg work still to do, a lot of people to speak to...we've made a quick arrest on this and that is a direct result of many, many police agencies who have been assisting us from the get-go with information they have. "
Police have said Monday's shooting was a targeted attack against John Raposo, who died from a shot to the head.
Another man, whose name isn't being released, was wounded in the crossfire, but police have said he wasn't an intended target. He is expected to survive.
The 35-year-old Raposo was known to police, but officials have not provided other details. Media reports suggest he may have had ties to organized crime but did not belong to a group himself.
Monday's shooting outside the Sicilian Sidewalk Cafe took place as dozens of soccer fans gathered at the gelato shop to watch a European Championship game.
At the time, the gunman was wearing a white hard hat, an orange safety vest with fluorescent green ``X'' on the front and back and had a white filter mask on his face.
Monday's incident came just two weeks after another broad-daylight shooting that rocked the city.
Gunfire erupted in the food court of the Eaton Centre shopping mall on June 2, killing one man instantly and sending several others to hospital. Another man died of his injuries last week.