Park’s final-round 74 gave her an eight-under total of 280 and a four-shot victory over I.K. Kim, who also carded a 74 for 284.
Park joined US sporting legend Babe Zaharias as the only women to win the first three majors in a season. Zaharias won all three in 1950.
“I’m very honored to put my name to someone like Babe Zaharias,” said Park, who became the first LPGA player to win the first three majors of a year in which at least four tournaments were designated majors.
“I didn’t feel that much of the pressure when I was on the golf course,” said Park, who will go for a fourth consecutive major at the Women’s British Open at St. Andrews in August.
“I was very nervous yesterday, but on the golf course I felt somehow very calm.”
After back-to-back bogeys at the sixth and seventh, Park rebounded with birdies at the ninth and 10th. Despite another brace of bogeys at 14 and 15, she was never seriously threatened.
Kim’s 74 left in second place on 284, and South Korea’s Ryu So-Yeon posted an even par 72 for sole possession of third place on 287.