Walker followed Larry Brown, who played with the Washington Redskins from 1969 to 1976 and Bonnie Sloan, who was a member of the St. Louis Cardinals in 1973.
Walker was subsequently followed by Flozell Adams, who played with the Dallas Cowboys and Pittsburgh Steelers from 1998 to 2010 and Derrick Coleman, a member of the Seattle Seahawks, Atlanta Falcons and Arizona Cardinals from 2012 to 2018.
At his final home game for the Cornhuskers, the capacity crowd showed their appreciation for Walker by signing "applause" to him in unison.
Following his time in the NFL, Walker played a short, three-season stint in the Canadian Football League with the Calgary Stampeders (1994-1995) and Winnipeg Blue Bombers (1995-1996), becoming the first deaf player in the history of the CFL.
In 2014, Walker was back in Denver, working as an assistant coach with the Highlands Ranch track team.