Two off the pace going into the final round at the Walt Disney World Resort, Love held off a stunning late charge by rookie Tommy Gainey by firing a sparkling eight-under-par 64.
Love, whose last Tour triumph came at the 2006 Greensboro Classic, piled up five birdies in seven holes from the 10th to forge two strokes clear of the chasing pack.
Despite missing the fairway off the tee on 17 and 18, he twice saved par, getting up and down from a greenside bunker at the last for a 25-under tally of 263.
Gainey, who has made only six cuts in 24 Tour starts this season, had to settle for second place after covering the back nine in a blistering six under for a matching 64.
Love, whose world ranking plummeted after a mediocre 2007 campaign ended prematurely with an ankle injury, was delighted to clinch his 20th Tour victory and a lifetime exemption.
"Thirteen months after ankle surgery, I've been grinding trying to get a win," he said with a broad smile in a greenside interview. "I can't believe it happened.
"I hit three bad drives today, two of them on the last holes, but I'm excited to get it in. It's been a lot of fun."
Love took early control in the final round, three birdies in the first five holes on the sun-drenched Magnolia course putting him one stroke clear.
However his playing partner Steve Marino drew level by knocking in a 10-footer to birdie the seventh and the pair reached the turn tied for the lead at 20 under.
Love and Marino each birdied the 10th and 11th before Love benefited from a two-shot swing at the par-four 13th.
Marino, seeking his maiden US PGA Tour title, bogeyed the 384-yard hole after hitting his approach into the front greenside bunker and failing to reach the putting surface with his third shot.
Love's drive ended up to the left of the green from where he struck a superb chip to 15 inches for a tap-in birdie.
The long-hitting Love sank a curling 25-footer to birdie the 14th and picked up another shot at the 16th, where he holed out from 20 feet, to move two ahead of the field.
He did well to save par at the 17th where he pulled his tee shot into the left rough, chipped out on to the fairway and struck his wedge approach to seven feet before sinking the putt.
Gainey, playing in the group ahead, signed off with a flourish after striking a superb approach to four feet on the final hole before watching Love coolly seal victory with a closing par.