Cox ended the tournament at 18-under-par 270 for a two-stroke victory over three players. His win was facilitated by chip-in birdies at his last two holes, but also by the collapse of another player looking for his first victory.
Overnight leader Camilo Villegas carded double-bogeys on consecutive holes late in his round and ended four strokes back in a tie for sixth place.
'Sometimes, it's your turn,' said Cox, who collected $85,500 for his first victory. 'This is phenomenal. I played pretty well all week and was able to make two pretty good chips there at the end.'
Jerry Smith carded Sunday's second-lowest round at 6-under 66 to finish tied for second place at 16-under-par 272. Joining him there were Craig Bowden (69) and Chris Tidland (68).
Villegas, a Nationwide Tour rookie, held the lead after the second and third rounds and was at 17 under before a bogey at the ninth dropped him back a stroke.
Cox was playing in the group ahead of Villegas and he rolled in birdie putts at the 10th and 12th to get to minus-16. Villegas also birdied those two holes to reach 18 under, but they would be his last two birdies.
Coming off two runner-up finishes in his last five events -- the Envirocare Utah Classic and the Oregon Classic -- Cox seized the lead on the final six holes Sunday.
The 31-year-old birdied 13 and bogeyed 16 to remain at 16 under, but Villegas was busy squandering his chance for a maiden win with double bogeys at the 14th and 15th.
Cox then watched as a 25-yard wedge shot at the 386-yard, par-4 seventh rolled into the cup for a birdie and a one-shot lead. He drove into the trees at 18, came up short of a bunker on his second shot and finally hit the pin from 50 yards out with his third.
The ball fell straight down into the cup for another chip-in birdie.
'I was honestly trying to hit the chip solid. It was sitting up pretty good,' said Cox, who won despite hitting just four of 14 fairways Sunday. 'I hit it too solid though. Somehow it hit the pin and dropped straight down. If it hadn't hit the pin it would have been 10 feet past the hole.'
With the win, Cox moved from No. 25 to No. 7 on the Nationwide Tour money list to assure himself a return trip to the PGA Tour in 2006.
Jeff Freeman finished in fifth place at minus-15 after a final-round 67, while Rick Price (67), Scott Weatherly (68) and Keoke Cotner (69) shared sixth place with Villegas.