Hall usually has her boyfriend, Harry Tyrrell, on her bag, but she chose to replace him with her father at Royal Lytham, and the move paid off as she claimed a memorable two-shot win and the title of Women's British Open champion.
On the 13th hole, Hall made a 10-feet birdie to move to 16-under and therefore a share of the lead.
Ahead of the final day, Hall trailed course leader Pornanong Phatlum by just one shot.
Ahead of a tournament in Abu Dhabi previous year, Hall hit a drive of 579 yards on Yas Marina race track, believed to be the world's longest drive by a female golfer.
With her father Wayne as her caddie, she came from a shot behind overnight Thai leader Pornanong Phatlum to post a 17-under 271 total and claim a first major title and the US$490,000 (S$669,000) winner's cheque.
But a 70 earned her second place on 15 under, with Ryu (70) another two shots back in third.
Hall joined Laura Davies (four), Alison Nicholas and Stupples as women's major winners from England.
Pornanong Phatlum of Thailand is standing out at the Women's British Open for more than just her pink golf ball.More news: Ohio State football coach Urban Meyer on administrative leave
Starting the day one shot off the pace, the world No.8 made bogey on her third hole before stringing together three birdies to head in the right direction.
Home favorite Georgia Hall (68) was in the tie for second place along with, who was leading by two strokes on 11 under when she lost her ball in a gorse bush at No. 17 and wound up with a double-bogey 6. I was loving it deep down, hitting the shots under pressure.
Roared on under blue skies by the large gallery desperate for a home victor, the 39th-ranked Hall started the day a shot behind Pornanong, who led after the second and third rounds. "I was so happy". "I can't show any emotion at all, it's just to try and keep her levelheaded really".
Hall added: "I was in the final round past year [at Kingsbarns] and that is definitely going to help me". She had six birdies in the round. "The British Open, home crowd and to play in England in front of so many fans and spectators, it's very special for me".
A week before defending his PGA Championship title, Justin Thomas on Sunday demonstrated that his game is in excellent shape as he blew away the field for a four-stroke victory at the World Golf Championships (WGC) Bridgestone Invitational in Akron, Ohio. He turned in a dud, and a birdie on the 18th hole gave him another 73 to leave him 15 shots behind.
Thomas had not had a score better than 67, and he had not finished higher than a tie for 28th in his two previous appearances at Firestone. Here JENNIFER DUNKERLEY tees off 10 fairway facts about her...
Playing in the final group with Rory McIlroy, the 25-year-old Thomas never let anyone closer than two shots of the lead. "He's one of the greatest players of all time", Perry said.