PINEHURST, June 23, 2014 (AFP) - The American, tipped for stardom even before she turned pro at the age of 15 in 2005, finished with a two-under total of 278, two strokes in front of world number one Stacy Lewis, who kept the pressure on with a final-round 66 for 280.
"I just had a lot of fun out there," said Wie. "I woke up so excited. I was so grateful for this opportunity."
Wie saw a three-stroke lead shrink to one with a double-bogey at 16. But she responded by burying a 25-foot birdie putt at 17 to take a two-stroke lead to the final hole.
- Goosebumps -
"I got a lot of goosebumps walking up 18," said Wie, who allowed herself a small smile and wave as she was greeted at the 18th green by a standing ovation.
Wie, swept along by a wave of hype and endorsements when she turned pro, drew criticism for her early insistence on trying to challenge in men's events before she had become a proven winner against the world's top women.
Sunday's triumph was her fourth on the LPGA Tour, and her second of the year.
In April, she won the Lotte Championship in her home state of Hawaii to end a victory drought stretching back to 2010.
The major title, on the course where Germany's Martin Kaymer lifted the US Open trophy in the second men's major of the season a week earlier, also helped erase the memory of her near-miss in the Kraft Nabisco Championship this year.
She went into the final round of the year's first major at Rancho Mirage tied for the lead but ended up second behind 19-year-old Lexi Thompson.
"Obviously there are moments of doubt," Wie said when asked if she ever wondered if she could win on the game's biggest stages.
"But at the same time I just had so many people around me ... they never lost faith in me. That's what kind of pushed me forward."
Lewis, who started the day six shots off the lead shared by Wie and South Korea's Amy Yang, posted an impressive eight birdies in her four-under 66.
That included a birdie-birdie finish that had her three shots behind Wie as she walked off the course.
"It feels great to finish the way I did," Lewis said. "I knew I needed to go out early today and post a number and make Michelle earn it."
Northern Ireland's Stephanie Meadow, playing her first tournament as a professional, carded a one-under 69 to finish third on one-over 281.
Yang struggled to a four-over 74 that put her alone in fourth on 282.
After an opening bogey, Wie strung together eight straight pars, including a good save at the par-four fourth where she was in a bunker off the tee and caught the lip of the trap with her second shot.
She landed her third shot three feet from the pin and made that.
While Wie stayed steady, her lead fluctuated between two and three strokes.
But after Lewis bogeyed 14, and Wie rolled in a nine-foot eagle putt at the par-five 10th, Wie again found herself with a four-stroke cushion.
Lewis dropped another shot at 16 before her birdie-birdie finish.
- Hard on herself -
Wie, meanwhile, followed her eagle with five pars. At 16, she was in the sand off the tee, and knocked her second shot into a small shrub.
She took an unplayable lie penalty, and her fourth shot left her 25 feet from the pin.
Wie ran her first putt five feet past, but made it coming back for the double-bogey that cut her lead to one.
"I kind of smiled after I made my double-bogey putt," Wie said. "I just like to make it hard on myself."
After her birdie at 17, Wie found the fairway at the final hole, and two-putted from 20 feet to seal the victory.
"Oh my god," Wie said. "I can't believe this is happening."
Leading final-round scores on Sunday in the US Women's Open golf championship at Pinehurst (USA unless noted, a-denotes amateur, par-70):
278 - Michelle Wie 68-68-72-70
280 - Stacy Lewis 67-73-74-66
281 - Stephanie Meadow (NIR) 71-72-69-69
282 - Amy Yang (KOR) 71-69-68-74
283 - Meena Lee (KOR) 72-73-70-68, Ryu So-Yeon (KOR) 69-74-70-70
284 - Lexi Thompson 71-68-74-71, Sakura Yokomine (JPN) 74-68-71-71, Pornanong Phatlum (THA) 71-73-69-71
285 - Catriona Matthew (SCO) 75-69-75-66, Jenny Shin (KOR) 74-70-73-68, a-Brooke Mackenzie Henderson (CAN) 71-73-72-69
286 - Feng Yue Er (CHN) 73-71-71-71, Choi Na-Yeon (KOR) 71-70-71-74
287 - Lydia Ko (NZL) 76-71-71-69, Feng Shanshan (CHN) 77-70-70-70, Brittany Lincicome 77-70-69-71, Park Hee-Young (KOR) 73-73-69-72, Paula Creamer 70-72-72-73, Chella Choi (KOR) 75-70-69-73, Juli Inkster 71-75-66-75
288 - Julieta Granada (PAR) 75-71-74-68, Sandra Gal (GER) 74-72-73-69, Karine Icher (FRA) 76-72-71-69, Azahara Munoz (ESP) 73-71-74-70, Brittany Lang 73-75-69-71, a-Minjee Lee (AUS) 69-71-72-76
289 - Ji Eun-Hee (KOR) 71-75-75-68, Caroline Masson (GER) 72-75-73-69
290 - Candie Kung (TPE) 71-76-75-68, Angela Stanford 71-72-77-70, I.K. Kim (KOR) 71-74-75-70, Mariajo Uribe (COL) 72-70-76-72, Karrie Webb (AUS) 70-73-70-77