Doug LaBelle II shot a 66 to finish alone in second place at 16-under-par 272. Former U.S. Amateur champion Bubba Dickerson was two shots off the pace at 15- under-par 273, while Chris Couch finished fourth at 14-under-par 274.
The 31-year-old two-putted for a birdie at the par-5 11th and moved to 16 under with a birdie at the par-4 12th. Gore found trouble with a bogey at the 14th, but he answered with an eagle at the par-5 15th and held on for the win.
'I've seen some pretty crazy things in the last three weeks,' said Gore, who struggled in the final round at Pinehurst and tied for 49th. 'It was such an experience to be able to be paired with Retief Goosen and to see how he handled adversity. It was just a wonderful week at the Open and an event better week this week.'
LaBelle jumped out of the gate with a birdie at the par-4 first and ran off three consecutive birdies starting at the par-4 sixth to move to 14 under. He rolled in a 7-foot putt for a birdie at the 11th to take the lead and added a birdie at the par-3 13th to expand his advantage.
The 30-year-old missed the green with his second shot at the par-5 15th, but rolled his third from off the green into the hole for an eagle to jump to 18 under. LaBelle's quest for the title was derailed with back-to-back bogeys from the 16th, however, and he managed a par at the last to take second place.
'I've still got some goals that I want to reach, but this is certainly a confidence builder,' said LaBelle.
Bubba Watson, Cliff Kresge, Nathan Green and Kevin Gessino-Kraft finished at 13-under-par 275 in a tie for fifth place. Olsen struggled with a 74 on Sunday to join Kris Cox and Tom Scherrer in a tie for ninth place at 12-under-par 276.