Lee drained five birdies in a stylish and stress-free three-under-par 67 at the testing Aronimink Golf Club to capture a share of the first-round lead at the PGA Championship in Pennsylvania.
In a promising start for the Australian contingent, 2015 champion Jason Day and 2022 Open winner Cameron Smith also finished in red numbers after both posted one-under 69s.
The day, though, belonged to Lee, who enjoyed the outright lead at four under late in his round before settling for a share of the lead for the first time in 19 major championship appearances.
The turnaround comes after the 27-year-old Perth prodigy ruefully missed the halfway cut at the Masters.
"We're all trying to get off to a good start. Over the last few months I haven't done that," Lee said.
"(I had) just a little bit of a mindset change to go out there and be aggressive instead of having that saying of 'you can shoot yourself out of a Thursday'.
"I've nearly taken that too far and played a little bit conservative. I'm hitting the ball really good, so why not go at some pins and make some putts?"
Lee bogeyed the first hole before finding his groove, his only other dropped shot coming at the treacherous par-3 eighth, his penultimate one of the day, after finding the deep rough short and right and failing to get up and down.
"It's great to start off well. It's tough, but it was kind of the right time to put the foot on the pedal a little bit and hit some shots that needed to be more aggressive than not," he said.
"I played great, didn't get myself in too much trouble.
"Drove the ball really well - every major you have to - but especially this course. The rough is pretty juicy and you don't want to attack the greens over in the rough."
Day cursed his putter after missing six birdie attempts inside 15 feet, but picked up two shots late to be well in the mix for a second PGA Championship title.
After missing the cut at the past six majors, Smith rediscovered his mojo after changing coaches pre-tournament.
The one-time world No.2 was three under through seven holes before ending the day alongside Day in a tie for 15th.
Adam Scott and Elvis Smylie both opened with two-over 72s but are still only five shots off the pace.
Travis Smyth has some work to do to secure a weekend tee time after starting with a 74.
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