Racing in the 400m freestyle, he won the gold medal by breaking his own world record. An hour after this triumph, Thorpe swam the anchor leg for Australia in the 4x100m freestyle relay. He came from behind to barely beat Gary Hall, Jr. of the United States in a thrilling finish. Two days later, Thorpe earned a silver medal behind Pieter van den Hoogenband in the 200m freestyle. Next he swam the leadoff leg for Australia's 4x200m freestyle relay team that went on to win in world record time. Although he did not participate in the final, Thorpe gained a fifth medal, a silver one, by swimming in a preliminary heat of the 4x100m medley relay.
At the Athens Olympic Games in 2004, Thorpe added four medals to his tally: a gold in the 200m freestyle with a new Olympic record of 1'44"71, another gold in the 400m freestyle, then a silver in the 4x200m freestyle and a bronze in the 100m freestyle. He also came 6th in the 4x100m freestyle relay. His victory in the 200m, the big race of the Games, ahead of the American Michael Phelps and Dutchman Pieter van den Hoogenband, gave him revenge for his surprise defeat by van den Hoogenband in front of his home crowd in Sydney in 2000. At 22, Thorpe is the most titled Australian swimmer in history.