A Waco, Texas native,Johnson was among the most dominant high school players of the decade, earning All-State honors at linebacker and leading the Waco Lions to the 5A quarterfinals both his junior and senior seasons. He was a two-time Parade All-American, the top linebacker recruit in the state, a member of the Texas Football Super Team and played in the inaugural U.S. Army All-American Bowl in 2001. At the University of Texas (2001-2004), Johnson was a two-time consensus all-American, four-time all-Big 12, Defensive Player of the Year, and recipient of the Dick Butkus and Bronco Nagurski Awards. in 2005, He was drafted in the first round by the Kansas City Chiefs in 2005 and was voted to three consecutive Pro Bowls from 2011-2013. He was inducted into the Texas Sports Hall of Fame in 2021.