But it was Hataoka who blistered Kemper Lakes Golf Club on Sunday with a round of 8-under 64 to storm from behind and move within one shot of Ryu, who had six holes to play when Hataoka signed her scorecard.
After Ryu banged in a 15-foot birdie from the fringe, Park matched her from nine feet to send the Korean pair to the par-four 16th. Park, who was four strokes behind, shot three birdies for a 69. Ryu had a 73. But once Ryu made a double bogey on the 17th hole by hitting her tee shot into the hazard, she allowed Park and Hataoka to share the lead, forcing a sudden-death playoff.
Park, Ryu and Hataoka all ended the 72 holes at 10-under 278, though they each took a vastly different route to get there.
Park had three career wins on the LPGA Tour coming into this weekend, including the U.S. Women's Open a year ago.
Americans Angel Yin (71) and Jessica Korda (69), on seven under finished tied fourth.
In taking the title she becomes just the third Korean to win the KPMG Women's PGA Championship. The 19-year-old's round was also the best of the day by three strokes and best of the tournament by two.
In regulation, Park was trailing Ryu by one stroke at 10-under, when she almost put her second shot into water short of the green.
The 20-year-old was playing her second Major of the year and had missed the cut at ANA Inspiration.
After heavy rain soaked the course earlier in the week, the past two days have been marked by brutal heat, with temperatures in the mid-90s on Saturday. And with storms forecast for late Sunday afternoon, organizers adjusted the start times and had groups of three tee off on the first and 10th holes.
Park and Ryu both missed good birdie chances at the final hole of regulation but proved quick learners at the same par-four to start the playoff.
Ryu took a three-shot lead on Park with a birdie at the 11th but gave back a shot two holes later. Ryu drained a 16-foot birdie putt to put the pressure on her two fellow competitors. It was a long way from her back nine score of 30 on Friday when every putt seemed to find the hole.
Henderson, of Smith Falls, Ontario, hopes to celebrate Canada Day on Sunday by claiming her second Women's PGA Championship title after winning the event two years ago when it was held in Seattle. The changes were effective for Park, as she had 27 putts in the final round and not a single bogey. She eagled the par-5 seventh hole and bounced back from a bogey on the par-4 No. 10 with another eagle on the par-5 11th.