At the 2025 World Aquatics Championships in Singapore, McIntosh became the first Canadian to earn four individual gold medals at a single world championships. She won the 200-m and 400-m individual medley, 400-m freestyle and 200-m butterfly. She also took bronze in the 800-m freestyle.
The win in 200 butterfly made her Canada’s first ever three-time world champion in an event. The 400 IM was also her third gold in the event, while the 400 free and 200 IM were first-time world titles.
McIntosh was named the Best Female Athlete of the World Aquatics Championships.
She became the first Canadian to take home five individual medals at one world championships. American Katie Ledecky (2015) is the only other woman to win four gold at a single worlds, and fellow legend Sarah Sjostrom of Sweden (2019) is the only other woman to win five individual medals (1G-2S-2B).
She extended her Canadian record for career individual medals at the long course World Championships to 11, and brought her overall career total to 13, the most by any Canadian in history.
McIntosh dominated at the Paris 2024 Olympic Games. Coming home with gold medals in the women’s 200 and 400 individual medley and the 200 fly, McIntosh became the first Canadian athlete to ever win three golds at a single Olympic Games, winter or summer.
She also earned silver in the 400 free, making her the first Canadian swimmer with four individual medals at the same Games, and tying Kylie Masse for most career individual medals with four.
She also set Olympic Games, world junior and Canadian records in both the 200 fly (2:03.03) and the 200 IM (2:06.56.
McIntosh also contributed to Canada’s fourth place finishes in the women’s 4×100 free relay, 4×200 free relay, and the 4×100 medley relay.
She was selected co-flag bearer for Canada at the Closing Ceremony
At the 2025 Bell Canadian Swimming Trials in Victoria, McIntosh dominated, winning gold in all five of her events. She broke world records in the 400-m freestyle, 200-m individual medley and 400-m IM. McIntosh also set Commonwealth and Canadian records in the 800-m freestyle and 200-m butterfly.
At the 2024 World Aquatics Swimming Championships (25m) in Budapest, Hungary, McIntosh won three gold medals and broke the world records in 400-metre freestyle, 200-m butterfly and 400-m individual medley. It was her first time swimming three world records at one meet, giving her six world record swims in her career.
Her 400-m freestyle win was her fourth world record, first world record at an international event and first world short course record.
She became Canada’s first ever world champion in the 400 free and 200 fly. At 18 years, 114 days, when she won the 400 free, she also became Canada’s youngest world short course champion.
McIntosh also took home a silver in the 200-m back (1:59.96) breaking the world junior record along with a bronze in the 4×100-m freestyle relay alongside Mary-Sophie Harvey, Ingrid Wilm and Penny Oleksiak.
To wrap up the 2024 season, McIntosh was awarded the Female Athlete of the Year by World Aquatics at the conclusion of the 25m championships.
At the conclusion of the championships, McIntosh surpassed Maggie Mac Neil for most individual world gold medals by a Canadian with seven. McIntosh and Mac Neil are the only Canadians to win gold at both long course and short course worlds.
McIntosh was named Swimming Canada’s Female Swimmer of the Year (Olympic Program) for 2024, her third straight year, and Junior Female Swimmer of the Year, her fourth and final.
She received the Northern Star Award as Canada’s top athlete, Canadian Press Female Athlete of the Year award, and was nominated for the Laureus Award in the breakthrough category. She was named to the TIME100 Next 2024 list and was the only aquatics honouree among Forbes’ 30 Under 30 sports figures.
McIntosh won four medals at the 2023 World Aquatics Championships in Fukuoka, Japan. That included two individual golds in the 200m butterfly and 400m individual medley along with two bronze medals in the 200m freestyle and 4x100m freestyle. The two golds gave her a total of four, moving her into first place all time among Canadian swimmers.
She established two world junior records and Canadian records in the 200m freestyle and 200m butterfly. McIntosh also broke the championship record in the 400m individual medley and the Americas record in the 200m butterfly.
At the 2023 Bell Canadian Swimming Trials, McIntosh broke the 400 freestyle and medley world records. She also broke the Canadian and junior world records in 200 freestyle, butterfly and IM.
McIntosh brought home 6 medals (2 gold, 3 silver, 1 bronze) from the 2022 Commonwealth Games. She broke the World Junior Record in the 200-m individual medley and in the 400-m individual medley and broke the Canadian record in the 400-m freestyle. Her 400 IM time was also a Commonwealth record and Americas record.
McIntosh broke the world junior record in the three individual events she swam at the 2022 FINA World Championships in Budapest. She won gold in the 200-m butterfly, breaking the world junior record in her semifinal as well as in the final, won gold in the 400-m individual medley and captured silver in the 400-m freestyle. McIntosh was also part of the women’s 4×200-m freestyle relay team that earned bronze. She lowered the world junior 200-m freestyle record in the first leg of the relay.
McIntosh became the youngest Canadian swimmer to win a gold medal at either a World Aquatics Championships or Olympics
At the Toronto 2022 FINA Swimming World Cup, she broke her Canadian and world junior short-course record to beat American legend Katie Ledecky in the 400-m freestyle, and set Canadian and world junior marks to win the 400 IM. She went on to win the 200 butterfly and break her 800 free Canadian record in a silver medal finish at the Indianapolis leg of the World Cup a few days later.
She lowered her 400 IM long-course Canadian record from Commonwealth Games at the U.S. Open in North Carolina in Dec. 2022.
McIntosh was named Swimming Canada’s Female Swimmer of the Year (Olympic Program) and Junior Female Swimmer of the Year for 2022
During the 2023 Pro Swim Series in Fort Lauderdale, Fla., a few weeks before Trials, McIntosh broke three junior world records over the course of three days in 200-m freestyle, 200-m butterfly and 200 individual medley.
At the 2021 FINA World Championships (25m), McIntosh was a member of the 4×200-m freestyle that won gold and broke the Canadian and Americas record. McIntosh also swam in the preliminaries for the women’s 4×100-m medley that went on to capture silver. Individually, McIntosh captured silver in the 400-m freestyle, and broke the Canadian record in the 800-m freestyle preliminaries.
At the Tokyo 2020 Olympic Games, Summer McIntosh made her Olympic debut by breaking the Canadian record in the 400-m freestyle preliminaries. She advanced to the final where she finished in fourth place and lowered the record again. McIntosh also finished ninth in the 200-m freestyle and placed 11th in the 800-m freestyle while setting a national age group record.
At the same event, McIntosh was a part of the 4×200-m freestyle team that broke the Canadian record and finished fourth. McIntosh also lowered the Canadian age group record in the first leg of the 4×200-m freestyle.
McIntosh broke the Canadian record in the 400-m freestyle at the 2022 Bell Canadian Swimming Trials. McIntosh went on to win gold in the 200-m freestyle, the 200-m butterfly, and the 400-m individual medley. Her performances qualified her for the 2022 FINA World Championships and the 2022 Commonwealth Games.
At the Tokyo 2020 Olympic Trials, McIntosh won gold in the 200-m & the 800-m freestyle. Her performance at the Tokyo 2020 Olympic Trials qualified McIntosh for her first Olympic Games at the age of 14.
McIntosh also swam an Olympic A qualifying time in the 400-m freestyle at the Swim Ontario Take 5 High Performance event a few weeks before the Trials.
McIntosh won Swimming Canada’s Breakout Performer of the Year and the Junior Female Swimmer of the Year awards in 2021
At the 2019 Canadian Swimming Championships, McIntosh captured silver in the 400-m freestyle and bronze in the 400-m individual medley and 800-m freestyle.
At the 2019 Canadian Swimming Trials, McIntosh finished fifth in the 200-m butterfly, seventh in the 800-m freestyle and ninth in the 400-m individual medley.