Walker played football at Stephen F. Austin University; once his stint there concluded, he signed with the AFL's Charlotte Rage.
Walker played for a succession of AFL teams over his ten-season career; these included the Orlando Predators, Arizona Rattlers, Indiana Firebirds, Chicago Rush, Austin Wranglers, and Las Vegas Gladiators.
In Walker's first season at the helm, the Hawks posted a pedestrian 8–8 record; they made the playoffs, however, behind the league's third-ranked defense.
The Iron allowed 903 points in Walker's first year (the eleventh-highest mark in the 14-team league); despite this, the team's defense finished second in sacks (25.5) and fourth in interceptions (20).
The unit was led by the return of defensive back Clevan Thomas, who had been elected to the AFL's Hall of Fame one year prior.
[9] Thomas led the league with fifteen interceptions (six of which were returned for touchdowns); he joined Sykes as the SaberCats' second consecutive Defensive Player of the Year.
At the end of the season, the SaberCats defeated the Jacksonville Sharks in ArenaBowl XXVIII; this gave Walker his second AFL Championship (and first as a defensive coordinator).