Walker went to Walterboro High School in South Carolina and was a letterman in football and track and field.

Walker was selected by the Arizona Cardinals with the 71st overall pick in the third round of the 2000 NFL draft, but was released before playing a game.

He was then traded on March 26, 2007 (along with a conditional 2008 draft pick) to the Buffalo Bills for linebacker Takeo Spikes and quarterback Kelly Holcomb.

However, there was a proviso to that trade stating that if Walker did not report to Bills training camp by August 5, 2007, he would be returned to the Eagles in exchange for a sixth-round draft pick in 2008.

[5] On July 29, 2007, the Buffalo Bills traded Walker's rights to the Chicago Bears in exchange for a 5th round draft pick in 2008 (which Buffalo later traded to the Jacksonville Jaguars in exchange for Marcus Stroud) (the Bears were in need of a defensive tackle after having waived troubled defensive lineman Tank Johnson in the 2007 offseason).