Thorpe first attracted attention outside of the sports world when at age fourteen he became the youngest male ever to earn a spot on the Australian national swimming team. In 1997 he won second place at the Pan Pacific Games in Fukuoka, Japan, where he impressed the media with his quiet reserve and well-spoken ways.
Thorpe's athletic acumen improved as he matured. Barreling through the water and traveling at 3.1 meters per stroke, his talent was attributed in part to his expansive reach. At 6-feet-5-inches tall and 215 pounds, he is not only tall, but also sports unusually large feet, which at size seventeen are seven sizes larger than the average adult man. This disproportionate big footedness, according to some critics, is his greatest asset as an athlete. His long and flexible feet provide excellent propulsion in the water and—to Thorpe's dismay—are often compared to flippers. His kick, a six-beat stroke, works like a small propeller, which he synchronizes with his arms at a ratio of six kicks to one upper body stroke. He swims like a highly efficient machine. South African swimmer Ryk Neethling compared the volatility of Thorpe's wake to the inside of a washing machine. Said Neethling, who was quoted in Sydney's Morning Herald, "It can be hell out there behind him; it is so much more turbulent than normal."
With continued guidance from Frost and Don Talbot, the Australian national coach, Thorpe swam to a world championship in the men's freestyle in 1998 at age fifteen. He was the youngest world champion in history of that sport. The win generated public speculation about his Olympic potential for the Sydney games in 2000.
Thorpe stunned the world at the Pan Pacific Games in May 1999 in his native Sydney when at age sixteen he broke the world record in the 400-meter freestyle. Thorpe, with a time of 3:41:83, shaved very close to three full seconds from the old record. In the 200-meter freestyle that year he logged a world record time of 1:46:34, which he personally bested at the same competition, to leave the world record at 1:46:00 by the end of the meet. In all, Thorpe set four world records in four days, including the fastest lap on record in the 4×200 freestyle relay. The Australians left with a total of thirteen gold medals and lauded Thorpe as their hero. "He could be the greatest swimmer we've ever had," Talbot was quoted by Time. "I have never seen anything like that," said former Olympian Randy Gaines, and Thorpe himself made no attempt to conceal his own amazement at the results of the competition.
In setting a world record at the new Olympic stadium at Sydney that year, Thorpe won a bonus prize of $16,000 for being the first to break a record in the new Olympic pool, which was built in preparation for the 2000 Olympics. Thorpe generously donated the money to cancer research and to a youth crisis prevention program. In part for his generosity, he was named Young Australian of the Year for 1999.
Australians love swimmers, and Thorpe as a sports prodigy attained near-superstar status, even before his first Olympic appearance. By the end of 1999, negotiations were underway for sponsorships and future endorsements. Banks, airlines, car manufactures, and others rushed to establish associations with Thorpe: Qantas, Adidas, Mazda, Sydney Water, and Omega, among others, joined his sponsorship team.