NAPA, 13 Oct, 2014 (AFP) - Bae, who took a four-shot lead into the fourth round, finished with a 15-under par total of 273 and a two-stroke victory over Australian Steven Bowditch.
"I tried to really enjoy my game, but I made a lot of bogeys," said Bae, adding that despite his four bogeys and three birdies in a one-over effort, "it was a really good experience."
Bowditch charged up the leaderboard with a five-under par 67 for 275.
Scotland's Martin Laird, who led after the second round, closed with a 71 to head a group on 12-under 276.
He was joined by Japan's Hideki Matsuyama (70), South African Retief Goosen (70) and Americans Bryce Molder (68) and Hunter Mahan (70).
The tournament at Silverado Country Club's North Course is the first stop on the US PGA Tour's 2014-15 season.
Bae was making his first start in the event and added the title to the Byron Nelson Championship crown he won in 2013.
The 28-year-old from Daegu hadn't managed a top-10 finish on the US tour since that victory.
Bae's last two bogeys, at 13 and 14, saw his lead dwindle to two strokes over Bowditch, but he scrambled to pars on the final four holes to secure the win.
"I think I was a little nervous," Bae said of his emotions down the stretch. "This course wasn't easy, honestly. I know how well I did. I'm very, very happy."
The tournament saw Australian Jarrod Lyle return to action for the first time on the US Tour since twice receiving treatment for leukemia.
After qualifying on Monday to play, he made the cut and finished tied for 31st, and called his week a "huge success."
"It's something to build on for the rest of the year," said Lyle, who will tee it up on Thursday in Las Vegas on a sponsor's exemption.
Leading final-round scores on Sunday in the US PGA Tour $6 million Frys.com Open (USA unless noted):
273 - Bae Sang-Moon (KOR) 66-69-65-73
275 - Steven Bowditch (AUS) 73-68-67-67
276 - Bryce Molder 70-69-69-68, Hideki Matsuyama (JPN) 70-67-69-70, Retief Goosen (RSA) 69-71-66-70, Hunter Mahan 70-68-68-70, Martin Laird (SCO) 67-67-71-71
277 - Hudson Swafford 70-69-71-67, Robert Allenby (AUS) 70-71-66-70, Jon Curran 68-72-67-70, Brooks Koepka 68-70-67-72
278 - Scott Brown 71-68-72-67, Lee Westwood (ENG) 73-69-69-67, Tony Finau 69-73-68-68, Derek Fathauer 70-71-68-69, Zachary Blair 69-66-69-74
279 - David Lingmerth (SWE) 68-68-70-73, Scott Langley 70-66-69-74
280 - Ryo Ishikawa (JPN) 71-71-67-71, Byron Smith 73-66-68-73
281 - Kevin Kisner 71-72-70-68, Brendan Steele 72-70-69-70, Scott Stallings 71-69-70-71, Spencer Levin 73-69-67-72, Matt Kuchar 71-68-66-76