American swimmer Aaron Peirsol is a world record holder and reigning 100 meter backstroke world champion. He won three gold medals at the 2004 Summer Olympics and was selected to join the U.S. Olympic swimming team at the 2008 Summer Olympics.

On August 11, 2008, Peirsol defended his 100 meter backstroke gold medal and broke his own world record with a time of 52.54 seconds. He also won a gold medal and broke the world record in the 4 x 100 meter medley relay and earned a silver medal in the 200 meter backstroke event.

Peirsol began competing internationally in 1999 and took home a silver medal in the 200 meter backstroke at the Pan American Games. He made his Olympic debut at the 2000 Summer Games, where he won silver in the 200 meter backstroke. Starting at the 2003 World Aquatics Championships, Peirsol has won the 100 meter backstroke event every year. He also won the 200 meter backstroke at the championships in 2001, 2003 and 2005. Peirsol swept the backstroke events at the 2004 Summer Olympics, taking home gold medals in the 100 and 200 meter backstroke events and the 4 x 100 meter medley relay.