Park, who tied the tournament record with a 19-under par 273, became only the second golfer to win the tournament three times in a row, following in the footsteps of Annika Sorenstam who won the event from 2003 to 2005.
In addition to tying Sorenstam's record, Park also dethroned Lydia Ko as the top-ranked women's golfer. The 26-year-old only needed to finish tied 29th to overtake Ko atop the rankings after the 18-year-old New Zealander missed the cut, and she did that and more.
Kicking off the day two strokes ahead of compatriot Sei Young Kim, Park extended her lead over Kim in a bogey-free round, her third in a row, that included five birdies.
Kim, who beat Park in a sudden death playoff at the Lotte Championship in Hawaii in April, was unable to pose much of a threat on Sunday despite making seven birdies during her round of 71.
The 22-year-old faltered numerous times along the way as she recorded bogeys on the third, fourth and 13th, along with a double-bogey on the par-five ninth.
American Lexi Thompson finished third following an impressive final-round 66, which consisted of eight birdies, including three in a row from the seventh to ninth hole, and one bogey.
Finishing one stroke behind Thompson was Brittany Lincicome, who won the opening major of the year, the ANA Inspiration.
Morgan Pressel and 17-year-old Canadian Brooke Henderson tied for fifth after they carded final rounds of 70 and 71 respectively.