Kim's key shot in the first round, an eagle at the par-4 16th hole, followed five birdies and put her in control.
"It was a thrilling day, but it took me a couple holes to get my head out of my way, I guess," Kim said. "It's funny to say, but I had defending runner-up jitters on the first tee."
In 2007, Kim finished second to Sherri Steinhauer.
Kristy McPherson and Jee Young Lee share third place at 7-under 65 while a group of five players share fifth at 6-under 66.
In her best career effort on the women's tour, Michelle Wie shot 5-under 67 to join six others in a tie for 10th place and Steinhauer shot 3-over 75.