Furyk trailed Immelman by one shot heading to the 18th hole, but ended up tied for the lead at 12-under-par 276 after Immelman three-putted for bogey from 45 feet.
But while Immelman laid up, landed short of the green on his third shot and came up 2 feet shy on a chip shot, Furyk played a brilliant second shot just short of the green, pitched within 4 feet and rolled in the putt for par and his 11th title on the PGA TOUR.
Furyk, who shot a 1-under 71 in the final round, lost in a playoff to Vijay Singh at last year's Wachovia.
'I've seen enough of 18 for another year, I promise you that,' said Furyk, who earned $1.134 million for the victory. 'I had to see it three times on Sunday last year and twice this time. So I've had enough.
'It's nice to come out and get it done this time and end up with a 'W''
Second place is Immelman's best finish on the PGA TOUR, ahead of his fifth- place tie at the 2005 Masters. He owns four international victories.
'Obviously when you come that close you're a little disappointed not to finish the job, but it's my best finish on the PGA TOUR and I've got to build on that,' said Immelman, whose final-round 70 included five birdies, one double-bogey and his bogey at the last.
Playing in the final group with Furyk and Immelman, Retief Goosen held the lead early in the round, drifted behind later on, and then collapsed with a quintuple-bogey on the 18th hole after hitting into the water three times.
Goosen shot a 5-over 77 in his final round and ended seven strokes back in a tie for 10th place.
Goosen's collapse left Australian Adam Scott with a distant and quiet third-place finish after a round of 1-under 71 put him at 8-under-par 280.
Bill Haas and Lucas Glover were one stroke further back in fourth place after rounds of 70 and 72, respectively.
Play was delayed by rain for about an hour in the morning. When it got back underway, it was clear that the battle for the lead was between the three players in the final group.
Furyk began the round with a one-shot lead over Immelman and Goosen, but it was Immelman who led around the turn after carding three birdies during a five-hole stretch from the fifth.
That put the South African at 13 under around the turn, but he fell into a tie for the lead with Goosen after his drive found the trees and he made double-bogey at the 11th.
Immelman got that shot back with a birdie at the 13th, giving him a one-shot lead over Furyk and a two-shot lead on Goosen, who had bogeyed 12.
At the par-5 15th, Goosen was the only member of the final group to find the fairway with his tee shot, but he managed only a par while Immelman and Furyk birdied the hole with putts of 6 feet and 15 feet, respectively.
Still leading Furyk by a shot at 13 under, Immelman was now three clear of Goosen. Which is how things stood at the 18th, where Furyk and Immelman both found the fairway with their drives.
Furyk played his second shot into the rough, then pitched within 8 feet. Immelman found the green, but was nearly 50 feet away and rolled his first putt 9 feet past the hole.
'I was just trying to read the speed,' said Immelman. 'In the back of my mind I knew if I was going to get picky I'd like to have an uphill one coming back, so I was probably going to over hit it rather than under hit it. Just hit it a few feet too hard.'
After Immelman missed his second putt and tapped in for bogey, Furyk deliberated for a few minutes over his par putt. When it dropped in on the left side of the cup, he pumped his right fist.
'I just wasn't quite sure -- I thought there was an argument that it could go right or left,' Furyk said of the putt. 'I didn't have a really good idea where to go with it, so I had to commit to something.'
Vaughn Taylor (71), Steve Lowery (72) and second-round leader Bo Van Pelt (75) shared sixth place at 6 under, while Geoff Ogilvy (71) was tied with Goosen one stroke further back.
Vijay Singh, the 2005 champion, shot a 9-over 81 to fall from a tie for eighth place overnight into a tie for 38th place at plus-3. His round included a triple-bogey at the 18th, seven bogeys and just one birdie.