Mhairi McKay and Lorie Kane finished tied for third at 5-over-par 221. Annika Sorenstam was one shot further back at 6-over-par 222 alongside Danielle Ammaccapane.
'From my practice time this morning, I knew it was going to be very difficult,' said Pak, who pocketed $225,000 for the win. 'And it was very cold as well. But obviously, after winning today, it was easy! I feel good.'
The strong winds and cold temperatures that made scoring soar during the second round remained at The Club at Nine Bridges. Pak, who struggled with a 76 on Saturday, found trouble out of the gate with a bogey at the par-3 second.
Pak settled down from that point on and drained a 12-foot putt for birdie at the ninth. She faltered with a bogey at the 11th but responded with a birdie at the very next hole.
The 25-year-old stumbled again with a bogey at the 14th but just as before she countered with a birdie at the following hole. Pak then parred the remaining holes to post a comfortable victory to the delight of the local fans.
'It was a great tournament,' said the Korean, who earned her 18th career victory on the LPGA Tour. 'There is always a lot of pressure coming back to Korea to play golf. I kind of just freed my mind and it feels really great to win this tournament.'
Pak earned her second straight victory on the LPGA Tour. She captured the Mobile LPGA Tournament of Champions two weeks ago and now has five titles to her name in 2002.
Koch posted a 1-over 73 during the final round for a total of 3-over-par 219.
'It was very tough out there, very, very cold,' said Koch. 'I'm very happy with my round, especially in these conditions. On the first tee today, I could only have dreamed of shooting 1-over par.'
Sorenstam, who needed a win at this event to keep her hopes of matching Mickey Wright for most victories in a single season on the LPGA Tour alive, was five shots back to start the final round and saw her chances vanish with four bogeys over the first five holes.
The Swede managed two birdies and two bogeys on the back nine for a round of 76.
Woo-Soon Ko finished alone in seventh at 7-over-par 223. She was followed by Suzanne Strudwick, Rachel Teske and Jill McGill at 8-over-par 224.
Grace Park, Mi Hyun Kim and Leta Lindley finished tied for 11th at 10-over-par 226.
Final scores from the Sports Today CJ Nine Bridges Classic