Playing the back nine first on a calm, sunny morning at Glen Abbey Golf Club, Steele mixed eight birdies with a single bogey for a seven-under 65 that left him a shot clear of compatriots Matt Kuchar and Scott Brown and Australian Scott Gardiner.
As breezes stiffened and conditions toughened for the afternoon starters no one managed to come close to nudging Steele, 30, from the top of the leaderboard.
Steele, whose has just one US PGA Tour win, had three birdies on his outward nine on the Jack Nicklaus-designed layout and picked up the pace after the turn with five birdies over seven holes before dropping his only shot of the day at the ninth.
Kuchar, the highest ranked player in the field at world number six, mixed an eagle with five birdies and a bogey while Brown turned in a flawless round with six birdies.
"It was perfect conditions," smiled Kuchar, who has made 20 consecutive cuts, including all 16 starts this season. "I feel like last week, conditions were so challenging and so difficult at the British Open to come here and play golf that is more friendly and more what we are use to was great."
Gardiner, who has made the cut just twice in his last 16 events, began his day with a par then reeled off six consecutive birdies to race up the leaderboard.
The Australian's red-hot start cooled with seven consecutive pars before he picked up another birdie at 15 followed by his only bogey of the day at 16.
American Hunter Mahan and Swede David Lingmerth were a further shot back after returning 67s while Chez Reavie, whose only career US Tour win game at Glen Abbey in 2008, and former Masters champions Bubba Watson and Trevor Immelman were among a large pack three off the pace.
"The first two days the afternoon wave is going to be tougher for sure," said Mahan. "In the morning the greens are pure and the wind is not blowing quite as hard."
Indeed, some of the tournament's biggest names were left floundering in the breezy conditions with former world number one Luke Donald of Britain (73), twice Canadian Open champion Jim Furyk (72) and 2010 US Open winner Graeme McDowell (76) all failing to break par.
American Woody Austin, who fired four sub-par rounds of 70 last week at the Sanderson Farms Championships to claim his first US Tour title in six years, crashed to the bottom of the leaderboard with a 10-over 82.
Reigning champion Scott Piercy began his title defense with 10 straight pars before signing for a one-under 71.
Without a homegrown winner in 59 years, local fans were out in full force to offer their support but could not inspire the Canadian contingent to anything better than a three-under 69 from Brad Fritsch that left him four back of the leader.
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