Lee wins LIV Tucson event
Lee, who defected to the lucrative Saudi Arabia-backed circuit last month, had not won as a professional since his victory in the 2015 PGA Tour Greenbrier Classic.
But the 32-year-old held his nerve in a four-player playoff to nail a 25-foot birdie putt on the second playoff hole to end his lengthy absence from the winner's circle.
"I haven't won since 2015," Lee said afterwards. "I just felt like winning is just not my thing, but today just changed that.
"It's just good to see I'm capable of playing some good golf again," added Lee, who collected $4 million in prize money with the win.
Lee had forced his way into the playoff after closing his final round with back-to-back birdies to card a two-under-par 69, leaving him nine under for the tournament after 54 holes.
That helped him into a playoff alongside Carlos Ortiz, Brendan Steele and South Africa's Louis Oosthuizen.
Ortiz was eliminated from contention after bogeying the first playoff hole.
After Oosthuizen and Steele missed their birdie putts, Lee knocked in his long-range effort from well off the green to secure victory.