The South Korean triumphed by two strokes from teen prodigy Lydia Ko, who took Park's world No. 1 ranking last month -- at 17 the youngest player of either gender to reach the summit.
Ko, born in Korea but raised in New Zealand, had to settle for second place at Sentosa in Singapore on Sunday -- International Women's Day
-- after winning her previous two events.
"She played great all week," Ko said of her 26-year-old rival, who will stay second when the new rankings are released next week. "No bogeys around here and on a course where you can hit a good shot and you can get bad luck. That's pretty phenomenal."
Park, who finished 15 under par, won not only $210,000 for winning the LPGA event but also $7,500 from a bet with her dad -- with the stakes at $500 for a birdie and $1,000 for a bogey.
"This week was just incredible," said Park, who has held the No. 1 ranking for a total of 73 weeks in two periods and now has career prize money of nearly $10.3 million.
"I don't think I can even believe myself that I didn't make any bogeys for 72 holes."
Park led the tournament from start to finish, and closed with two-under-par 70 -- a score matched by Ko -- as she claimed her 13th LPGA Tour title.
She has now played 92 holes without dropping a shot, going back to the third round of last week's Honda LPGA Thailand, where she tied for seventh.
"It's good to have a family here and they are big energy," said Park, who got married last October.
"This week just went so quick. I didn't have to think about golf when I'm not on the course, so I think that was a big help."
Former world No. 1 Stacey Lewis finished third, two shots behind Ko, as the American finished with a par 72.
"It was fun being in the final group. That's where you want to be. But even par usually doesn't cut it," said Lewis, who won the tournament in 2013.