Johnson shot a 7-under 65 at Glen Abbey to match Kevin Tway, Byeong Hun An and Whee Kim at 17-under 199.
“I like the golf course, I feel like my game’s in really good form, I’ve got a lot of confidence in it,” said Johnson, who tied for second at Glen Abbey in 2013 and 2016.
Johnson birdied the first three holes and five of the first six, then rebounded from two back-nine bogeys with a birdie-birdie-eagle run. He’s seeking his third victory of the season and 19th on the tour.
“I’m going to have to go out and play really well tomorrow,” Johnson said. “There’s definitely low numbers out here. There’s a lot of guys right around the lead and somebody’s going to go shoot low. Hopefully it’s me.”
Tway, the second-round leader, had a 68. He’s trying to win his first PGA TOUR title in the event where father Bob Tway won the last of his TOUR titles 15 years ago.
“I looked (at the leaderboard) a little bit. He started off really hot,” Tway said about Johnson.
An shot 66, and Kim 67.
“Chasing the lead or holding the lead, it doesn’t matter. Just play your game,” Kim said. “Everybody’s going to say the same thing. It doesn’t matter.”
Mackenzie Hughes was the top Canadian. He was tied for 13th at 11 under after a 67.
Johnson insists he’s only popular in Canada by proxy — fiancee Paulina Gretzky is the daughter of NHL great Wayne Gretzky.
“Well, I can thank Wayne for that,” Johnson said. “There’s a lot of Gretzky fans out there, and so they tend to pull for me, which, `Thanks, Wayne, I appreciate that.’ I do get a lot of love up here, and the fans have been great this week.”