The victory was not enough to regain her world ranking but sets her up well for a successful defence of the US Women's Open title in two weeks.
After a slow start to the event on Thursday, Park needed something special over the closing 54 holes and today she put the finishing touches to a spectacular fightback with a final round of 61 to win by three over Cristie Kerr who might have imagined a round of 63 on Sunday when in contention might well have been good enough.
China's Shanshan Feng finished 3rd while New Zealander Lydia Ko and Spain's Belen Mozo tied for 4th.
Newly crowned Stacy Lewis finished one shot further back in 6th position after an encouraging final round of 63.
Sarah Kemp and Sarah Jane Smith were the only Australians to make the cut but finished a long way back.