Mickelson finished at 14-under-par 266 after spinning a wedge back to three feet to set up a final birdie at the 18th. He closed with a six-under 64 and notched the 21st victory of his PGA Tour career.
'To win this tournament the last two years is a cool feeling,' said the 32- year-old lefthander, who collected the $720,000 first prize for his second win of the season.
Mickelson, who captured the Bob Hope Classic in his first start of 2002, joined Tiger Woods as the only multiple winners on the PGA Tour this year.
Mickelson, clearly a crowd favorite last week when he finished second behind Woods in the U.S. Open, received the same strong support this Sunday as he made his way toward the amphitheater surrounding the 18th green at the TPC at River Highlands.
'There's nothing greater than the feeling walking up 18 and feeling the support from the crowd and the community and everyone who is involved with this tournament,' he said. 'To be able to experience that from a player's perspective is an incredible feeling.'
Love had an opportunity to tie Mickelson but missed an 20-foot birdie putt on the 18th and posted a 67. Kaye, bidding for his first win, also had a chance to force a playoff with a birdie at the last but badly pushed his 12-foot attempt to the right of the cup. He shot an even-par 70 to tie Love for second place at 13-under 267.
Scott Verplank, tied for the lead early on the back nine, made two bogeys on the way in and finished with a one-over 71. He was alone in fourth at 11- under.
Joel Edwards' 63 was the best round of the day and lifted him into a tie for fifth place with Jim Carter (68) at minus-10.
Mickelson began the day at eight-under and broke into double-digits under par with a 15-foot birdie at the second hole and a 12-footer at the fourth. He then tied Kaye and Verplank for the lead at 12-under by holing a sand wedge from over 100 yards for eagle at the par-four seventh.
He three-putted for bogey at the par-three eighth, however, horseshoeing out a par putt from 2 1/2 feet.
After bombing a drive of over 300 yards down the fairway at the 462-yard 10th, Mickelson hit a wedge to 15 feet for a birdie to return to 12-under. He got up and down to save par from over three green at 11, then came up one revolution short on a 25-foot birdie try at the 12th.
Mickelson's vaunted short game helped produce a birdie at the par-five 13th. His three-iron second shot wound up just right of the green and he chipped up to tap-in range to seize the lead at 13-under par.
Then Kaye, who was one-over for the day through 12 holes, got into the eagle action at the 13th when he spun his third shot with a sand wedge back into the hole to leap-frog Mickelson and move to minus-14.
Mickelson made a brilliant save at the 14th, where his drive found the left rough and his approach clipped a tree. His ball came to rest in a sandy downhill lie well short of the green but he managed to chip to within five feet to set up an important par.
At the short but tricky par-four 15th, Mickelson's tee shot with a three-wood ran through the green and down a slope behind it. Another skillful chip left him with a four-foot birdie.
He quickly went from tied for the lead at 14-under to leading outright when Kaye failed to save par from four feet at the 14th.
Mickelson tightened up the leaderboard after landing in a fairway bunker off the tee at the par-four 17th. His long shot from the sand went over the green, and he chipped to eight feet and missed the putt for a bogey five.
He made up for the poor drive at 17 with a monstrous poke of over 330 yards at the 444-yard 18th. Left with 110 yards in, Mickelson knocked his wedge approach to the rear of the green and it spun back past the edge of the cup. After successfully negotiating the remaining three feet for birdie, Mickelson headed to the putting green with his family to wait out the finish.
Kaye had chances to pick up shots down the stretch. He missed a six-foot birdie putt at the 15th and an uphill 10-footer at 16, then two-putted from long range to par the 17th.
Kaye didn't give himself much of a shot when he drove into the rough between bunkers right of the 18th fairway. Though he did very well to carry a seven- iron 195 yards to the back of the green, his putt to force extra holes never had a chance.
'I had plenty of opportunities,' said the 31-year-old Kaye, who finished second for the fourth time in his career. 'I just couldn't shake a putt in when I needed to. That was the difference.'
Love, whose year started off shaky with five missed cuts in his first 10 starts, posted his best finish of the season and his third top-five showing in the last six events.
'I'm making improvements,' Love said. 'Obviously, at the beginning of the year, I wasn't playing up to my standards. But I'm pretty happy with the state of my game.'
Full-Field Scores from The Canon Greater Hartford Open