2015 Henderson set a tournament record with her 36-hole score at the LPGA Tour's
Swinging Skirts LPGA Classic in April 2015, at the
Lake Merced Golf Club, just south of
San Francisco. Her second round 65 (−7) gave her 135 (−9), breaking the record set by
Stacy Lewis in 2014 by three shots. She finished third, one stroke behind
Lydia Ko, the playoff winner, and runner-up
Morgan Pressel. At age 17, Henderson had to play her way into LPGA Tour events through
Monday qualifiers, and to rely on sponsor exemptions, after her request for an age waiver to compete at the
LPGA Tour Q School in late 2014 was denied. She earned a
Symetra Tour card after winning her first event as a professional, the Four Winds Invitational in
Indiana in June
2015. With a final round 66 (−4), Henderson tied for fifth at the
U.S. Women's Open in July. After Monday-qualifying for the
Cambia Portland Classic in
Oregon in August, Henderson won the event by eight shots, the largest victory margin on tour since
2012, and became the tour's third-youngest winner. She was only the second Monday qualifier to win on tour, Henderson was also the first Canadian to win on the LPGA Tour since
Lorie Kane in
2001,
2016 In June
2016, Henderson won her first major championship, at the
KPMG Women's PGA Championship at
Sahalee Country Club near
Seattle. Her final round 65 (−6) propelled her into a tie with top-ranked
Lydia Ko, followed by a playoff which Henderson won with a
birdie on the first hole. At age 18, she became the youngest to win that major, the second-youngest in any women's major, and the first Canadian woman to win a major
in 48 years. It was Henderson's second tour win, both in the
Pacific Northwest, and her first as a tour member; it moved her from fourth to second in the
world rankings. Before the
2024 Women's PGA Championship at Sahalee Country Club, the club provided Henderson with an honorary membership and a commemorative plaque at the spot in the 18th fairway where she hit a 7 iron close to the hole to win the 2016 event. With her win as defending champion at the Cambia Portland Classic in June 2016, Henderson joined
Sandra Post and
Lorie Kane as the only Canadians to win multiple LPGA events in the same season. Henderson was a member of the
Canadian Olympic Team for the
2016 Summer Olympics in
Rio de Janeiro in the
women's Olympic golf tournament, placing seventh.
2017 In June
2017, Henderson won the
Meijer LPGA Classic. Her win on 2 October 2017 at the
McKayson New Zealand Women's Open was her first LPGA championship outside North America.
2018 On 14 April, Henderson won the
Lotte Championship, her sixth victory on the LPGA Tour finishing at −12 to win by four strokes over
Azahara Muñoz. On 26 August, Henderson became the first Canadian in 45 years – after
Jocelyne Bourassa in 1973 – to win the
Canadian Women's Open at the Wascana Country Club in
Regina, Saskatchewan. By finishing second (to
Ariya Jutanugarn) in the 2018 season-ending
Race to the CME Globe, Henderson was awarded $150,000 from the bonus pool purse. She was awarded the
Bobbie Rosenfeld Award in December 2018 as The Canadian Press Female Athlete of the Year for the third time.
2021 Henderson won the
Hugel-Air Premia LA Open on 24 April 2021 for her tenth LPGA Tour victory. Henderson won her second career major at the
2022 Evian Championship, in which she was the first player in LPGA history to begin a major with two rounds of 64 or lower. On 12 November, the day after shooting a first round, one-over-par 71 at the
Pelican Women's Championship, she wrote in a statement that she had to withdraw, "due to an injury in my upper back, it was recommended that I rest as much as possible coming into the week. While I plan to address any medical concerns and recover fully in the off season, I am trying to do everything I can to compete this week. I appreciate all of the support."
2023 On 22 January, Henderson won the 2023
Hilton Grand Vacations Tournament of Champions at
Lake Nona Golf & Country Club in
Orlando, completing all four rounds in the lead, and achieving her 13th victory on the LPGA Tour. In July, Henderson finished second to
Céline Boutier at the
2023 Evian Championship, the season's fourth major tournament.
2025 On 24 August 2025, Henderson won her second
Canadian Women's Open at the
Mississaugua Golf & Country Club near Toronto, Ontario, Canada, her 14th win on the LPGA Tour. Henderson won by a single stroke in a close final round duel with playing partner
Minjee Lee. ==Amateur wins==