Reilley Rankin struggled with a 75 to take fourth place at 4-under-par 212. Hee-Won Han and Heather Bowie tied for fifth place at 3-under-par 213.
Rosales held a two-shot lead over Rankin to start the final round on the Palmer Course at Turtle Bay Resort Golf Club and picked up her first birdie of the day at the par-5 third. She then hit her approach to 8 feet for a birdie at the par-4 sixth to stretch her lead to four.
The 26-year-old found trouble at the following hole, however, and sent her second shot into the water. Rosales walked away with a double bogey but maintained a two-stroke edge over Kerr.
'I was hitting good and sticking to my plan,' said Rosales. 'Then at seven I pushed my driver to the right and got a crappy lie. I was thinking I should lay up but got too greedy and I still tried to hit it out and paid for it.'
Kerr got within one of the lead with a birdie at the eighth, but Rosales countered at the ninth and drained a 14-foot putt for a birdie to get to 10 under.
Rosales missed the green en route to a bogey at the 13th and dropped another shot with a bogey at the 15th. Despite the late blunders, Rosales was able to hang on for her second career victory on the LPGA Tour.
'That course woke me up,' said Rosales, who took home $150,000 for the win. 'It was a fun week. When I got here I played to win and played great.'
After Kerr closed the gap to one with her birdie at the eighth, back-to-back bogeys from the 10th dropped the 27-year-old four shots off the pace. She stumbled to another bogey at the 13th but countered with a birdie at the very next hole.
Kerr bogeyed the 15th but responded again with a birdie at the par-4 16th. She then parred her way in to join Wie in a tie for second after a round of 72.
Wie commanded large galleries all week playing in front of the hometown fans and the amateur put together a strong finish after a difficult front nine. The 15-year-old collected a pair of bogeys and a birdie over her first nine holes but got back on track with back-to-back birdies starting at the par-4 11th.
At the par-5 18th, Wie played her third shot inside 4 feet and ran home the birdie try to post her third straight round of 70 and her best career finish on the LPGA Tour.
Rosie Jones, Carin Koch, Gloria Park, Tina Barrett, Nicole Perrot and Catriona Matthew shared seventh place at 2-under-par 214. Sung Ah Yim followed at 1-under-par 215.