The 23-year-old rookie bettered Brenden Pappas (67) by one shot. Sonny Skinner (65) and overnight leader Matt Peterson (71) finished tied for third at 16-under, two shots back of Byrd.
'I was trying to make birdies out there, I was trying make birdie at 18,' said Byrd. 'You can't let up out here. There are so many good players out here that if you try to make pars, you're going to get left in the dust.'
Byrd comments on his win in Greenville
Byrd entered the day trailing Peterson by three shots, but played his first six holes in 4-under to play himself into contention. Byrd birdied the 1st and 3rd holes, and then eagled the par-5 6th.
Meanwhile, Peterson was struggling early, posting a pair of bogeys on the 2nd and 3rd holes.
The nine-year tour veteran never recaptured the lead. He finished his day with four birdies and three bogeys.
At the 10th, Byrd caught a bit of luck. He drove into a fairway bunker and pushed his approach left, however it kicked off a hill and rolled down onto the green, five feet away. Byrd converted that birdie but bogeyed the par-3 11th when he three-putted from 35 feet.
Byrd rebounded from the putting mistake at 11 with back-to-back birdies at 12 and 13. He played his approach at 12 over the pin but the ball spun back to four feet. At 13, Byrd got on in two at the par-5 hole and two-putted from 45 feet.
Still riding the back-nine roller coaster, Byrd bogeyed the 15th, only to again notch consecutive birdies on the 16th and 17th holes.
Leading by two with one to play, the former Clemson All-American flew his approach shot over the green on the par-4 finishing hole.
Following a free drop near the spectator stands, Byrd salvaged a bogey, and his first professional victory.
Byrd collected $90,000 for his maiden triumph and moved from 71st to fourth on the 2001 money list.
Full-field scores from the Buy.Com Charity Pro-Am at the Cliffs