Stupples was born in Dover, Kent. She started her golfing career as a caddie for her father at Prince's Golf Club, Sandwich to earn pocket money.[1] She played for England Juniors from 1989 to 1991 and England Seniors from 1995 to 1998.[2] She also represented Great Britain & Ireland on the Curtis Cup winning team in 1996 at home in Killarney, Ireland[3] and losing 1998 team away in Minneapolis, Minnesota.[4]
Stupples was going to study polymer science in the UK before deciding to go to university in the United States.[5] With the assistance of College Prospects of America, she took a golf scholarship at Arkansas State University before transferring to Florida State University in 1993.[6] As a Seminole, she won two events (Spring 1994 Spalding/Peggy Kirk Bell and Spring 1995 Lady Gator),[7] was selected as All-Atlantic Coast Conference in 1994 and 1995, and was also named a 1995 Second-Team All-American.[8]
Despite being a professional, Stupples returned home to England becoming a cloakroom attendant for the Port of Dover and waitressing at a public golf course in Kent[1] as she did not have the money to take a run at LPGA Qualifying School.[10] When a regular restaurant customer offered to sponsor her for three years, she and her husband sold their house, furniture and car and moved to the United States[11] where she earned non-exempt status on the LPGA Tour by tying for 52nd at the 1998 Final Qualifying Tournament.[9]
Stupples made her professional debut in Hawaii[5] and, after a season in which her best finish was a tie for 8th, she returned to the LPGA Final Qualifying Tournament, where she tied for 17th to earn exempt status for the 2000 season. Over the 2000 - 2003 period, she achieved 7 top ten finishes,[9] but her form transformed in 2004.
After finishing second behind Annika Sörenstam at the ANZ Ladies Masters in Australia, Stupples carded the best 72-hole raw score in LPGA Tour history (258) to win her maiden title, the Welch's Fry Championship, by five strokes. This win made her eligible to join the Ladies European Tour and begin earning points for the 2005 Solheim Cup.[12] She had not joined the LET when joining the LPGA as she could not at the time afford the joining fee of £600.[13] She followed this up by winning the Women's British Open at Sunningdale where she became only the second player in history to record a double eagle or albatross at an LPGA major championship (began the final round with an eagle, albatross on the first two holes).[14] She became only the third English player to win a major after Laura Davies and Alison Nicholas.[15] and was the first home winner since Penny Grice-Whittaker in 1991.[14] She crossed the $1 million mark in LPGA career earnings at the U.S. Women's Open and finished in sixth place on the money list.[9]