Starting the final day two shots ahead of previous major champions Anna Nordqvist and Brooke Henderson at Philadelphia’s Aronimink Golf Club, Kim shot seven birdies — four in five holes on the back nine — to finish five shots clear of fellow South Korean and three-time Women’s PGA champion Inbee Park.
As well tying for the lowest round in the tournament’s history, the 27-year-old Kim also set a championship scoring record of 266.
It means she can no longer lay claim to being the LPGA’s most successful player without a major, adding Sunday’s victory to her 10 previous Tour titles.
“I’m so excited, I’m actually really hiding my tears at the moment,” Kim said after the win. “It was a major that I really wanted so very excited and happy that I got it done.
“I stuck to my gameplan, just focused one shot at a time. I didn’t want to play like this was my final round but just stick to my momentum that I played (with) all week and that worked out.”
Park, who won her three Women’s PGA Championship titles between 2013 and 2015, shot a final-round five-under but still finished five shots adrift of Kim, later saying her compatriot was “really untouchable” on the final day.
Behind Park in the final leaderboard was Spain’s Carlota Ciganda and Japan’s Nasa Hataoka, both of whom also profited from strong final rounds to finish seven-under.