 Walker started and played three matches for the United States Men's National Team, including a 1-0 shutout win over Mexico on April 28, 2004 His first cap was against Denmark in January 2004.Walker has been very involved with the Leukemia and Lymphoma Society, giving free soccer clinics to kids who raise the most money through their soccer club for the Soccer Kicks for Cancer program.In 2005, Walker was named the Ambassador for the State of Tennessee for the Leukemia and Lymphoma Society.