From 2019 to 2021, Jack served a 24-month competition ban for an anti-doping rule violation relating to unintentional use of Ligandrol.

She started swimming at the age of 18 months, after her parents thought it would be helpful to teach her and her siblings how to be safe in water.

It was later revealed that Jack had tested positive for the anabolic agent ligandrol, which is popular with bodybuilders, during an out-of-competition test held by the Australian Sports Anti-Doping Authority (ASADA); a follow-up sample further confirmed the banned substance in her system, and she was subsequently suspended by Swimming Australia and investigated by ASADA.

[13] At the 2022 World Aquatics Championships, with swimming competition contested at Danube Arena in Budapest, Hungary in June, Jack won her first medal of the championships in the 4×100 metre freestyle relay, splitting a 52.65 for the fourth leg of the relay to help win the gold medal in a final time of 3:30.95.

[18] On 10 August, following her medal-winning performances at the 2022 Commonwealth Games, Jack was named to the 2022 Duel in the Pool roster for Team Australia.

[24] She was awarded an Order of Australia in 2025 for her service to sport as a gold medallist at the Paris Olympic Games 2024.