At the 2020 Summer Olympics held in Tokyo, Japan, McKeon won four gold medals. She swam the third leg of the 4 × 100 metre freestyle relay for the Australian team, which won the gold medal in a world record time of 3:29.69. On the second last day of swimming, she also went to win the 100 metre freestyle in a time of 51.96 (an Olympic record and the second fastest time in history). On the last day, she won the 50 metre freestyle with another Olympic record time of 23.81 and swam the butterfly leg in the gold-medal winning team for the 4 × 100 metre medley relay.