Despite doing a time trial of 53.40 seconds, with her 100-metre performance of 56.39 from 5 months earlier in March and having hip problems, she was scratched from the women's 4 × 100 metre freestyle.

In Rome she finished with a bronze, beating compatriot Libby Trickett and ending 0.02 of a second off the Commonwealth Record.

In 2010, Cate and her sister Bronte caught glandular fever; they worked against post-viral fatigue as they trained to qualify for the 2012 Summer Olympics in London.

[17] Cate Campbell was a member of the Australian team that won the gold medal in the 4 × 100 metre freestyle relay at the Games.

[19] In the women's 50 metre freestyle she and Bronte swam in the same heat, finishing third and second respectively, and qualifying for the semi-final in tenth and ninth place respectively.

[21] On the sixth day of competition, Campbell won the 100 metre freestyle world title with a time of 52.34 seconds.

[22] Campbell finished ahead of Sarah Sjöström of Sweden and defending Olympic champion, Ranomi Kromowidjojo.

At the 2015 World Championships in Kazan, she won gold in the 4 × 100 metre freestyle relay, beating the Dutch and US teams by a comfortable lead.

[27] In addition, Campbell also qualified for the Olympic team in both the 4 × 100 m freestyle (winning gold in a new world-record time) & 4 × 100 m medley relays.

[28] At the 2016 Australian Grand Prix meet, she broke the long course 100 metre freestyle world record in a time of 52.06.

This was 0.01 seconds faster than the previous world record set by Britta Steffen during the super suit era.

At the 2016 Summer Olympics Campbell won a gold medal as a member of the Australian women's 4 × 100 m freestyle team.

[31] At the 2017 Australian Short Course Swimming Championships she broke the 100 metre freestyle world record in a time of 50.25, improving the previous mark by 0.33 seconds.

On 7 July 2021, she was announced as one of Australia's flagbearers for the Opening Ceremony, alongside basketball player, Patty Mills, and becoming the first Australian female swimmer to do so.

[37] Alongside Emma McKeon, Meg Harris, and sister Bronte, Campbell won gold in the women's 4 × 100 m freestyle relay, again breaking Australia's previous record.

[38] She then went on to win the bronze medal in the 100m freestyle, behind Emma McKeon (gold) and Hong Kong's Siobhan Haughey (silver).

Half an hour later, she and the Australian team won gold in the women's medley relay, alongside Kaylee McKeown, Chelsea Hodges and Emma McKeon.

After receiving a standing ovation, she confirmed her retirement in a special post-race interview and bid an emotional farewell to the Chandler crowd - the same pool where Campbell begun her competitive career.

Campbell's competitors paid homage to her for setting the standards in sprint freestyle nationally and internationally, as well as for being an inspiration in and out of the pool.