TURNBERRY, 2 Aug 2015, (AFP) - A 12 under par 276 total gave the 27-year-old world number one a three-shot triumph and a second major of the season to set alongside her third successive LPGA Championship in June.
Park has also won two US Opens and the 2013 Kraft Nabisco Championship.
The only missing major from the list is the Evian Championship - but she did win the title the year before it became one of the big five in 2013.
"I have dreamed of this,” said Park after becoming the seventh woman golfer to win four different majors in her career.
"It’s just amazing and it hasn’t really sunk in.
"Winning majors always gives you a confidence boost and that’s what made the difference today. I had been in the position before and I knew I could do it.”
Ko Jin-Young, the 20-year-old Korean LPGA player, was three shots behind in second place after a 71, with world number two Lydia Ko (69) and Ryu So Yeon (68) tied for third on eight under par.
Three behind going into the final round, Park was still three behind Ko Jin-Young with five to play.
But she eagled the 14th, birdied the 16th and finally unnerved her young compatriot.
Ko, a joint overnight leader, holed massive putts for an eagle at the seventh and birdies at the eighth and tenth to take control.
But she made her first error when she three-putted for bogey at the 13th - and that slip-up coincided with Park’s eagle at the 14th.
Her title hopes finally ended when she dumped her second shot into the burn guarding the green at the 16th. She ended up with a double-bogey six.
It was a sad end following a brave effort from Ko.
She was playing in her first major and had never experienced the tormenting wind and rain that accompanied every round of the championship.
Park was full of praise for her young compatriot.
"She is a very talented player and held up very well under the pressure. She played fantastic golf all week," said the champion.
"The weather made it so hard. But to overcome all the hard tasks and become champion is great. I putted so well today. Everything seemed to go in and nothing seemed to worry me.
"I’ve put my name on every single major championship. I won Evian before it became a major so it would be good to win it again this year.
"Winning this title was the only goal I set myself this year and I feel so happy to have achieved it. Every major is special but this one is much more special.
"This week I was lucky. I got the good side of the draw and some good bounces.”
At 18, Lydia Ko was right in the hunt to become the youngest ever major winner until she came to grief at the par four 12th.
The New Zealander took two in a greenside bunker - she had to hit out backwards with her second attempt to escape - and ran up a double-bogey six.
Norway’s Suzann Pettersen, the halfway leader, mounted a threat with three early birdies, but she fell away with back-to-back bogeys at the tenth and 11th.
Ryu, the 2011 US Women’s Open champion, finished her round with a brace of birdies to secure her share of third spot.
Spain’s Luna Sobron shot a fine last day 69 for a one under par total and won the Smyth Salver for the best amateur.
She was the only one of the six amateurs to make the cut.
Leading final round scores Sunday at the Women’s British Open at Turnberry (par 72):
276 - Park Inbee (KOR) 69 73 69 65
279 - Ko Jin-Young (KOR) 68 71 69 71
280 - Ryu So Yeon (KOR) 67 72 73 68, Lydia Ko (NZL) 66 73 72 69
281 - Suzann Pettersen (NOR) 68 69 72 72
282 - Teresa Lu (TPE) 68 71 69 74
283 - Anna Nordqvist (SWE) 69 72 73 69, Mika Miyazato (JPN) 68 72 70 73
284 - Amy Boulden (GBR) 71 74 68 71, Melissa Reid (GBR) 73 70 69 72, Minjee Lee (AUS) 69 72 70 73
286 - Maria McBride (SWE) 79 66 69 72
287 - Luna Sobron (ESP) 70 77 71 69, Cristie Kerr (USA) 66 77 73 71, Kim Hyo Joo (KOR) 65 78 73 71, Yani Tseng (TPE) 72 72 72 71
288 - Lee Mi Hyang (KOR) 70 75 74 69, Hannah Burke (GBR) 74 72 71 71, Stacy Lewis (USA) 70 75 72 71, Lexi Thompson (USA) 71 75 70 72
289 - Nanna Koerstz Madsen (DEN) 70 78 76 65, Lee Jung Min (KOR) 70 75 76 68, Angela Stanford (USA) 69 78 73 69
290 – Lee-Anne Pace (RSA) 75 73 74 68, Feng Shanshan (CHN) 71 74 76 69, Yoo Sun Young (KOR) 71 73 74 72, Nicole Broch Larsen (DEN) 69 74 70 77