Jeon shot a final-round 69 to tie Kerr at 7-under-par 209. Kerr, who held a four-stroke lead with six holes to play, had the title won in regulation, but missed a 3-foot par putt at the 18th to create the extra session.
On the seventh extra hole, No. 16 at Las Vegas Country Club, Jeon's tee ball found the right rough while Kerr was in the fairway. Both players battled swirling winds throughout the round and the wind caused Jeon to finally make a mistake.
She hit a 5-wood from 170 yards out and it flew the green and bounced some 30 yards behind the putting surface. Kerr knocked her second shot onto the right fringe.
Jeon tried to fly her third shot back onto the green, but her pitch caught a low hanging limb and came up short of the green. She then knocked her fourth some 50 feet past the pin.
Jeon rolled her fifth shot within 4 feet, but it did not matter. Kerr pitched her third to four feet and calmly rolled in the par putt for the win. The playoff was the second longest in LPGA Tour history behind only to the 10-hole extra session at the 1972 Corpus Christi Civitan Open, which was won by Jo Ann Prentice.
The first six extra holes were less than spectacular. Both golfers two-putted for par from within 20 feet on the first extra hole. Kerr seemed to have the advantage on the second extra hole, but only managed a par, which Jeon matched.
'It kind of turned into a match play situation,' Kerr said. 'You hit putts firmer than you would normally hit them and the Solheim Cup has really kind of given me a lot of experience. I would say that gave me a little edge.'
The duo each two-putted for par on the 16th from the right fringe to extend action to the 17th, the fourth playoff hole. There, Jeon rolled in a 15-footer for par before Kerr sank a 7-footer on top of that.
Jeon had a chance to win on No. 18 but her birdie try slid over the left edge and with two pars it was back to the 12th. Jeon again missed on the left side giving Kerr the life she needed as Jeon would struggle on the 16th, the final playoff hole.
Kerr had parred the first eight holes of regulation to remain clear of the field. She got up-and-down for birdie on the ninth to move to minus-9. She came back with a birdie at the next. Kerr drained a 20-foot birdie putt on No. 12 to move four strokes clear of the field.
Things started to go downhill from there. She knocked her second over the green and into a bunker on 13 and that led to a bogey. At the par-3 14th, her tee ball came up short and she was unable to save par there.
'I played really, really well until the 13th hole,' said Kerr, who picked up $165,000 for the win. 'I think I got a really bad gust of wind and I hit it solid. I hit it in the worst possible spot. I made a critical 15-footer for bogey there.'
Kerr lost her tee shot right off the 15th and that led to her third straight bogey and dropped her into a share of the lead with Jeon, who had birdied the 13th.
Jeon bogeyed the next, however, to give Kerr the lead back. However, Kerr was unable to convert her short par-saving putt at the last and the bogey forced the extra holes.
'I had a lot of fun out there,' Jeon said. 'I missed some putts and she missed some putts. I learned a lot from Cristie. She is a good player.'
For Kerr the win was just her second in seven tries when taking the lead to the final round.
'You know, I finished second in my career probably eight times and maybe three of those times I had leads going into the back nine where I faltered and I lost the tournament,' said Kerr. 'But I think knowing that that can happen, but I can still win, is going to be a big thing for me going into the future.'
Gloria Park fired a 5-under 67 to climb into third place at 6-under-par 210. Mi Hyun Kim carded a closing 70 to finish one shot behind Park.
Heather Daly-Donofrio, who played in the final group, ended at 4-under-par 212 alone in fifth place. That was her best finish since tying for seventh twice in the 2002 season.