Walker attended the University of Washington, where he was a member of Phi Gamma Delta Fraternity. While there, he became NCAA indoor pole vault champion twice and four-time NCAA All-American under Coach Pat Licari. In 2005 he became both indoor and outdoor National Champion.
Perhaps not among the favorites in the 2005 World Championships, Walker nonetheless won the silver medal with 5.75. Two weeks later in Rieti he set a new personal best of 5.96. In 2006 he won the World Indoor Championships in Moscow with a jump of 5.80meters. In July 2006, at Jockgrim, Germany, Brad Walker, cleared 6 meters, the best performance of the year, in a pole vault competition. He won the gold in the world championships on 1 September 2007. On 8 June 2008 Walker jumped in Eugene to a new personal and American record with 6.04. Walker qualified for the 2008 Olympics, but failed to clear a height in the preliminary rounds.