Quinn had a tournament-record 15-under 265 total at Panama Golf Club.
"I made it interesting for everyone," said Quinn, the 44-year-old Massachusetts native who took a five-stroke lead into the final round.
"I've never had a big lead like that before and I just put it on cruise control instead of trying to keep making birdies."
Smock closed with a 67. Tommy Gainey (67) finished third at 10 under, and Kevin Chappell (67), D.J. Brigman (69), Marco Dawson (70), Mark Anderson (72) and Argentina's Julio Zapata (73) tied for fourth, seven strokes behind Quinn.
Quinn opened with rounds of 66, 66 and 62, then held on as the wind picked up in 90-degree heat Sunday.
"I started out and just striped it," Quinn said. "I played really well the first seven holes, but missed four putts inside of 6 to 8 feet. I missed putts and duffed a chip on a par 5. I felt like I could have been 4 under at that point but was 2 over. I think I held onto the steering wheel a little too tight."
Smock was the only player to put any real heat on Quinn.
"When someone has a lead like that, the only thing you can do is to try and apply some pressure," Smock said. "You can't make bogeys out here. If you do you just make it easier on him. I think I was four shots back starting the back nine and I thought if I could shoot 3-under I might have a chance."
Quinn, who finished No. 25 on the Nationwide Tour money list last year to earn a PGA Tour card, will return to the big tour next week for the Honda Classic.