The 40-year-old Hoffman had six birdies in a seven-hole stretch that ended on No. 15. He bogeyed the par-4 17th and then rebounded with a two-putt birdie on the par-5 18th.
“When you’re playing good, I always say golf is fairly easy,” Hoffman said. “It’s been a fun run the last month or two months, actually all year, and it’s not very stressful, which is good.
“When you’re trying to make cuts, that’s when golf is hard. … Have my family out for the next five weeks. They are off for summer break. It’s been fun to hang out and go over to Europe with them and Canada. It’s been a good, fun summer vacation.”
Hoffman had a 17-under 199 total. He won the Valero Texas Open in 2016 to claim his fourth PGA TOUR title.
“Anything can happen in the last four or five holes,” Hoffman said. “Guys can make eagles, birdies, bogeys. Anything can happen. Obviously, want to get off to a good start on the front nine and play the back nine the way I need to and see how it goes.”
Kevin Chappell was second. He bogeyed the 18th, hitting his third shot into the water.
Robert Garrigus matched the course record with a 62 to join Gary Woodland at 15 under. Garrigus had two eagles and six birdies to tie the Glen Abbey mark set by Leonard Thompson in 1981 and matched by Andy Bean in 1983, Greg Norman in 1986 and John Merrick in 2013.
“Kind of started off with that eagle on 2,” Garrigus said. “Missed the green short, like a 30-footer up the hill, through the rough — through the first cut and rolled onto the green and went in.
“Next hole, I stuffed it in there. I chipped in on the par 3 and stuffed it on the other par 3 and made it, and I chipped in on 8, and I’m just thinking, `Oh, my gosh, what is going on right now. I’m not going to think about anything. I’m just going to keep going.'”
Garrigus finished before Hoffman started play.
“When you look at the board before I even tee off, someone shoots 62, you know the birdies are out there,” Hoffman said. “Perfect day here in Toronto to make some birdies and have some fun in front of the fans here.”
Woodland followed his second-round 63 with a 68.
Defending champion Jhonattan Vegas had a 67 to join Sam Saunders (67), Andres Gonzales (66), Tony Finau (66), Ryan Ruffels (68) and Brandon Hagy (69) at 14 under.
Second-round leader Martin Flores had a 72 to drop into a tie for 16th at 12-under par.
The top-ranked player in the FedExCup playoff standings, Dustin Johnson, finished the third round at 12-under total after carding a 68 on Saturday.
“I feel like the game’s starting to come back in good form,” Johnson said. “Other than a drive here and there, it was a really good day.”
Vijay Singh, the oldest player in the field (54), shot a 71 that left him 11 under. He won the 2004 RBC Canadian Open at Glen Abbey, beating Canadian Mike Weir in a playoff.
Matt Kuchar shot a 70, leaving him tied for 41st at 7 under. Coming off a second-place finish in The Open Championship, he fought dizzy spells in the first round on Thursday.
Graham DeLaet and Mackenzie Hughes, the only Canadians to make the cut, struggled on Saturday. DeLaet (73) was 7 under, and Hughes (74) was 6 under.
“It’s disappointing for sure,” DeLaet said. “You want to play well here. Maybe I was trying a little bit too hard. It was still fun. The crowds were awesome and I’ve still got tomorrow.”