The Knoxville, Tenn., native came from two strokes back to tie Pinneo at the end of regulation, then birdied the first extra hole to win the $20,000 prize for first place.
"It's a great feeling," said Reeves after the win.
He won the four-day tournament with rounds of 65, 68, 66 and 65 for a total score of 264. After entering Sunday's round tied for sixth place, Reeves was able to tie Pinneo for the lead with a 65, draining an eagle on hole 12 and a birdie on 13.
After his impressive round in regulation, his chances looked bleak in the playoff when his tee shot drifted right and came to rest on the side of a steep bank in the rough.
"You always want a good lie in the rough," he said, "but I got a lie that was almost too good."
His ball was on a mound of grass some four inches high.
"I knew there was a water hazard on the left and a bunker on the right where the ball would bury, so I aimed straight at the pin," he explained.
The ball landed short of the green, spun back some 40 feet and came to rest on a slight uphill rise.
"I hit a bump and run with an eight-iron and just tried to stroke it like a putt," he said.
The ball barely nudged the flagstick and dropped in for a birdie.
Pinneo, whose approach shot landed on the far back of the green, 60 feet from the hole, ran his tying putt attempt by the hole.
The Fayetteville, Ark., resident was five under on the front side on Sunday, but managed only even par on the back-nine for a five under par 67. Pinneo took home $9,250 for second place.
The tournament win moved Reeves up to No. 1 on the tour's money list with $78,338. He also became the first tour player to win two events this season, also claiming an event in Rock Hill, S.C., back in April.
Tee McCabe and David Dyer tied for third place and won $5,750 each. Brent Winston came in 5th place to claim $3,675. Former champion Michael Connell tied for 31st place and won $980.