Born and raised in Verona, WI, Walker quickly became an outstanding age group and high school swimmer under coach Randy Trowbridge. Walker came to UT as a freshman in 1994 and was a huge influence on Longhorn teams for the next 14 years. Under Eddie Reese and Kris Kubik, Walker earned 25 all-American awards, back-to-back NCAA individual titles and six Big 12 conference titles. He was also a member of the 1996 NCAA championship team. He set an NCAA record in the 50-yard freestyle and swam the 100-yard back in 44.92 seconds, setting an American, U.S. Open and NCAA record. Competing for Team USA for 10 years (1997-2007), including the 2000 & 2004 Olympic Games, Walker earned 17 gold medals, eight silver medals and one bronze medal. He was elected USA National Team captain in 2005, 2006 and 2007. During the last few years of his competitive career, Walker started coaching part-time with Longhorn Aquatics under Randy Reese. Shortly after retiring from swimming in 2008, Walker moved to Dallas with his wife April, became Rockwall ISD Aquatics Director, and head coach of the Rockwall Aquatics Center of Excellence (RACE) swim team. He also started the Rockwall Swim School.