The 39-year-old Kerr broke the tournament record at 20-under 268, a day after shooting 62 at Ko Olina to match the event mark. She earned $300,000 to top $18 million in her career.
Kerr ended a 30-event victory drought since the 2015 season finale. She was 16 under the final two days, soaring into contention with the third-round 62 that included seven back-nine birdies. She made six more birdie putts in the final round, taking the lead on the 14th hole.
The American overcame sponsor invite Su-Yeon Jang, the South Korean player who led after the second and third rounds and was five ahead of Kerr after three holes Saturday.
Jang had a 70 to drop into a tie for second with top-ranked Lydia Ko (64) and In Gee Chun (67).
Third-ranked Ariya Jutanigarn (69) and Stacy Lewis (6) were 14 under.