The Australian birdied the final three holes with putts of 15 feet or less Sunday to become the fifth PGA Tour player to reach the low-round record and win the Greenbrier Classic by a shot.
He also broke a four-year winless drought, when third-round leader Jeff Overton narrowly missed a long birdie try on the par-3 18th that would have forced a playoff.
"I was quite comfortable," Appleby said. "It's not a nerve-racking thing to be involved in. I had a lot of opportunities and I made them. It was great to do that to win the tournament." Appleby's 11-under round on the Old White course put him at 22 under. Overton, playing three groups behind Appleby, shot 67 to finish at 21 under.
"I did the math. I was chasing Jeff, who was heading toward the finish line," Appleby said. "At the same time I was playing well and I thought if I could keep making birdies ... I knew I was going to run out of holes. There was plenty of (birdie chances) coming in."
Appleby's round came less than a month after Paul Goydos shot a 59 at the John Deere Classic.
The others to shoot 59 were Al Geiberger at the 1977 Memphis Classic, Chip Beck at the 1991 Las Vegas Invitational and David Duval at the 1999 Bob Hope Classic.
Appleby had nine birdies and an eagle in his round to earn the $1.08 million winner's check.
He saw playing partner D.A. Points flirt with a 59 on Saturday before settling for a 61.
On Sunday, it was Appleby's turn.
"It was nice to be on the receiving end," Appleby said.
Appleby won for the first time since the 2006 Houston Open. His previous career low was 62 in the 2003 Las Vegas Invitational.
Appleby's achievement was the first 59 on a par-70 course. Goydos' came on a par 71 and the others on par 72s. Appleby understands there might be some debate as to whether his achievement is right up there with the others.
"I agree," he said. "I can see both sides of the fence. It is a number. I shot that number. But who says par is supposed to be 72? There's a lot of great courses that aren't 72."
Appleby didn't have the advantage of lift, clean and place that Goydos and Geiberger enjoyed, even though overnight rains left mud on some balls.
Appleby trailed Overton by seven strokes to start his round, shot 6-under 28 on the front nine and eagled the par-5 12th before settling for three straight pars.
He got his momentum going again just in time with birdies of 15, 10 and 11 feet on the final three holes.
Standing over his putt on 18, "I knew what it was all about," Appleby said. "I knew I had to make it - I knew I had to make it for the tournament, I knew I had to make it to have a 59. I'm sitting there going 'How many opportunities are you going to get to do this?
"The cards had been laying out perfectly for me all day. Why wasn't I going to do one more? I just got a good look at it and just - bang - it felt good."
Appleby's feat toppled the course record of 60 set by Sam Snead in 1950 and matched Saturday by J.B. Holmes.
The 39-year-old Appleby has played 11 straight weeks and will do it again starting Thursday at the Bridgestone Invitational in Akron, Ohio.
Overton had 34 putts in the final round, three-putting three times.
"I got beat by a 59," said Overton, who had his third runner-up finish of the year and remains winless in five years on the Tour. "What can you say? I played great, hit a lot of great shots. You can't win golf tournaments when you putt it that bad."
Brendon de Jonge (65) finished third at 17 under. Tied at 15 under were Points (70), Woody Austin (63), Paul Stankowski (64), Roger Tambellini (65) and Jimmy Walker (67).