Kang ended the three-day tournament at 15-under-par 201 for a four-stroke victory, the first of her career.
'I'm very happy that I won the tournament,' said Kang, who collected $210,000 for the victory. 'I practiced hard and put a lot of effort into it, so I guess that was the result.'
Joo Mi Kim (71) ended two strokes further back in fourth place, one stroke ahead of Sung Ah Yim (72) and Beth Daniel (70), who shared fifth place.
Pat Hurst (71), Rosie Jones (72) and Amy Hung (72) tied for seventh at minus-6, while 2004 champion Hee-Won Han led a group of eight players one stroke further back in 10th place.
Kang had never led an LPGA event heading into the final round, and she had just three career top-10 finishes before this win,
But the 29-year-old Korean wasn't phased. She birdied three of her first five holes at Columbia Edgewater Country Club, including the par-3 second with a 60-foot putt.
That put her at 15 under for the tournament, and she went on to birdie the par-5 seventh after hitting a wedge within 3 feet.
Kang dropped a stroke at No. 9 and made the turn at minus-15. But she got that stroke back with a birdie at the 12th, where her tee shot struck a tree and bounced fortuitously into the fairway.
'Before that hole, J.J. (Jeong Jang) was keeping pace and trying to come after me,' said Kang. 'But after that birdie, you know, I felt confident I was going to win.'
Jang was at 13 under par around the turn after collecting birdies at four of the last five holes on the front nine, but could never catch her playing partner and fellow Korean, who was three strokes ahead after 12.
Kang strung together five straight pars before dropping a stroke at the 18th with her second bogey of the day. Jang stumbled to two bogeys without a birdie on the back-nine.
'I still like second place...it feels like I have another win,' said Jang. 'My swing was really good [the] last couple of days, and my putting was really, really good. And everything was really good.'
Sharing 10th place with Han at minus-5 were Sherri Steinhauer (69), Jill McGill (70), Heather Daly-Donofrio (71), Johanna Head (72), Natalie Gulbis (73), Jean Bartholomew (73) and Aree Song (75).