"I had a lot of good moments today and I drove the ball well and hit a lot of wedges," Uihlein said. "But it wasn't until my 17th hole or the eighth hole of the course, where I birdied to get to 11 under that I thought about a 59."
Jim Furyk became the sixth player on the PGA Tour to reach the 59-mark at the BMW Championship two weeks ago.
This was the 17th time a player shot 60 on the European Tour. Branden Grace of South Africa did it on the same Kingsbarns course last year on his way to winning the tournament.
Lewis birdied three of his closing five holes to break clear of a crowded leaderboard, while Joost Luiten of the Netherlands was a shot back after finishing his round with four straight birdies for a 63 on Kingsbarns.
Lewis is looking for his second tour victory after capturing the 2011 Portugal Masters in just his third professional start. Since then, he's managed just one top-10 finish and slipped to 657th in the world.
"There wasn't much wind out there and 7 under really was not the worst it could have been but it definitely could have been a lot better," Lewis said. "I've probably left it a little too late to have a good season but then it doesn't mean it's the end of the world."