Brenden Pappas was on his way to matching the course record at Annandale Golf Club, but a costly bogey at the par-5 18th left him one shot short of the mark and opened the door for Huston's late surge. Pappas fired a 10-under 62 to finish alone in second at 19-under-par 269.
Huston carried a two-shot lead into the final round and was in control early. He landed his second shot inside 16 feet for an eagle at the par-5 fifth and two-putted for a birdie at the par-5 seventh that moved him to 19 under.
The 42-year-old soon found trouble with a bogey at ninth after he was unable to save par from four feet out and missed the green at the par-3 12th en route to another bogey. Just like that, Huston found himself trailing a charging Pappas.
Pappas picked up his first birdie of the day at the opening hole and knocked his approach to six feet for a birdie at the third. He ran home a 25-foot putt for an eagle at the fifth and dropped his third shot inside nine feet for a birdie at the seventh.
The 33-year-old ran home a 30-foot putt for a birdie at the 10th and made it two in a row with a birdie at the 11th. Pappas then ran off three consecutive birdies from the 13th to move into the lead at 19 under.
Pappas reached 20 under with a birdie at the 17th after his approach stopped 15 feet from the cup and the hard-hitting South African had a realistic shot at 59 with the par-5 last remaining.
Pappas missed the fairway off the tee at the 18th, however, and bogeyed the hole to stand in the clubhouse at minus-19.
'All in all I felt good,' said Pappas. 'I'll go away with a lot of positive thoughts.'
Huston regained his composure and hit his tee shot within four feet of the hole at the par-3 15th and landed his approach inside 12 feet for a birdie at the 16th.
At the par-4 17th, Huston hit his second shot over the water and watched as the ball stopped within three feet of the cup. Huston converted the birdie putt to regain the outright lead and parred the 18th for his first victory since the Tampa Bay Classic in 2000.
'It is hard when you go long spells,' said Huston, who pocketed $540,000 for the win. 'Better players than me have gone longer. To win, it is hard to do.'
Hidemichi Tanaka, Chris Anderson and Paul Stankowski shared fourth place at 16-under-par 272.
Jose Coceres, Tim Clark and Glen Day were one shot further back at 15-under- par 273.
Luke Donald, who earned his first career victory on the PGA Tour at this event last year, carded a 71 to join John E. Morgan and Russ Cochran in a tie for 10th at 14-under-par 274.