The boy's parents and younger sibling were injured when they were hit during the Sunday night accident in the patio of Ric's Grill, the Canadian Broadcasting Corp. reported.
The 62-year-old driver had not yet been charged but police said alcohol may have been involved, the CBC said.
"Absolutely horrible. A family comes out to enjoy dinner on a lovely night like this ... and who would think that you'd be in peril from traffic?" police Inspector Brian Nolan said.
"It's mind-boggling, it really is."
The crash occurred when the car sped up as it was being driven into a parking spot, Nolan said.
"For reasons at this time unknown, [the car] accelerated heavily, mounted the curb, took out the glass partition and struck the table where this family of four were and ran them over," the inspector said.
The boy's mother was treated for glass shards embedded in her legs, while his father had rib and back injuries and a 1-year-old sibling received only scratches.