[5] She completed her secondary education in 2012 from The Illawarra Grammar School[6] and following graduation, at the age of 18, relocated to Brisbane to train under Vince Raleigh at the Chandler Aquatic Centre in 2014.

[7] In 2015, McKeon switched coaches again and began training under Michael Bohl, initially at Brisbane's St Peters Western Swimming Club[8] before the pair relocated to Griffith University on the Gold Coast in 2017[9] where McKeon studied a bachelor's degree in public health and health promotion with a major in nutrition.

[5] McKeon was selected as part of the Australian team for the 2016 Summer Olympics, held in Rio de Janeiro, Brazil.

As part of the 4 × 200 metre freestyle, McKeon swam the second leg of the race and with a split of 1:54.64, helped Australia earn a silver medal with an overall time of 7:44.87.

McKeon swam a 56.95 in the butterfly leg of the 4 × 100 metre medley relay, collecting a silver medal as Australia finished with an overall time of 3:55.00.

[15][16] Her feat equalled the most medals won by a female athlete in any sport at a single Olympic Games, tying Soviet gymnast Maria Gorokhovskaya.

[20] McKeon swam the second leg of the 4 × 200 metre freestyle relay in a 1:55.31 split, helping Australia to win the bronze medal and set a new Oceanian record in an overall time of 7:41.29.

[22] McKeon anchored the mixed 4 × 100 metre medley relay final, and with a 51.73 freestyle split helped to win the bronze medal with an overall time of 3:38.95.

[24] On the last day of competition, McKeon swam the butterfly leg of the 4 × 100 metre medley relay in a 55.91 split, her efforts helping Australia collect the gold medal and set a new Olympic record in an overall time of 3:51.60.

[25] In 2013, McKeon won a silver medal in the 4 × 100 metre freestyle relay at the 15th FINA World Championships held in Barcelona, Spain.

[35] As part of the 4 × 100 m mixed medley relay, McKeon swam the butterfly leg in a 56.51 split, and with an overall time of 3:41.21, the team set a new Oceanian record and helped themselves to the silver medal.

[37] In the 4x200 metre relay the Australians broke the world record setting a time of 7:41.50 with McKeon swimming the anchor leg in a split of 1:54.90.

McKeon also earned a silver medal swimming the butterfly leg of the 4×100 metre medley relay final with a 56.44 split with an overall time of 3:53.37.

[45] As part of the 4 × 100 metre freestyle relay, McKeon swam the third leg and in a split of 52.91 helped Australia to the gold medal and set a new world record time of 3:30.98.

[47] As part of the 4 × 200 metre freestyle relay, McKeon kicked off the race in a split of 1:56.01, and with an overall time of 7:49.90, Australia earned the gold medal and set a new Games record.

[49] McKeon's six medals equalled a Commonwealth Games record for swimmers previously set by Ian Thorpe and Susie O'Neill.

McKeon started the 4 × 200 metre freestyle relay with a 1:56.62 split, which helped Australia win the gold medal and set a new Games record in an overall time of 7:48.04.

As part of the 4x100 metre medley relay, McKeon split a 56.42 for the butterfly leg to help Australia win the gold medal and set a new Australian All Comers record with an overall time of 3:54.36.

[58] McKeon anchored the women's 4 × 100 metre freestyle relay final and with a 52.04 split help to win a gold medal with an overall time of 3:30.64.

[62] In the women's 4 × 100 metre medley relay, McKeon swam a 56.59 split for the butterfly leg and with an overall time of 3:54.44, earned the gold medal.

[64] In her final event of the program, McKeon swam a 55.36 in the 100 metre freestyle preliminary heats to advance through to the semifinals after qualifying in sixth position.

The ISL is an annual professional swimming league featuring a team-based competition format with fast-paced race sessions.

[66] McKeon was the overall highest scoring female competitor at the short course 2021 FINA Swimming World Cup stop in Budapest, Hungary.

[87] Her entries in sprint events for both freestyle and butterfly at the fourth and final stop of the World Cup circuit, located at the Palace of Water Sports in Kazan, Russia for the year, were noted by FINA as races to watch during competition.

"[102] McKeon's performances across all four stops of the World Cup made her the highest overall scoring competitor of any gender, coming in at 228.3 total points and $144,000 of prize money.

[106] At the Australian Short Course Swimming Championships held in Sydney, New South Wales in August 2022, McKeon swam a light schedule, competing in just two events.

[107] McKeon started her campaign swimming a 51.76 split in the women's 4 × 100 metre freestyle relay in the preliminary heats to advance first through to the final.

[116][117] In the 50 metre freestyle, McKeon swam a 23.93 in the preliminary heats to advance sixth into the semifinals, where she qualified second for the final in a time of 23.51.

[121][122] As part of the women's 4 × 100 metre medley relay, McKeon split a 53.93 for the butterfly leg and with an overall time of 3:44.92, collected a silver medal.

[150] In April 2022, McKeon began dating musician turned swimmer, Cody Simpson, although the couple did not confirm their relationship until July of the same year.