Johnson started six games and had 19 tackles, three sacks and four tackles for a loss of 11 yards. He was placed on the six-game injury list after getting hurt in Game 7. He began the season on the one-game injury list.
Johnson played in 12 games at defensive tackle and recorded 16 tackles including a tackle for a loss, one special-teams tackle, two sacks and one interception. He played two games before suffering a torn oblique and was placed on the nine-game injury list. He returned to the line-up ahead of schedule for the Labour Day Classic. He was hurt in the final regular season game and was on the injury list for the Western Final.
Johnson played linebacker for four seasons at Kentucky. As a senior in 2009, he led the Wildcats with 105 total tackles including 6.5 tackles for loss. He added one sack. In 2008, he was a first-team Southeast Conference all-star as he recorded 93 tackles despite missing two games due to injury. He led the Wildcats and was third in the SEC with 13 tackles for loss. Johnson had 58 tackles and two interceptions in 12 games as a sophomore in 2007 and was named the SEC all-freshman team in 2006 after making 29 tackles and recording one forced fumble and one fumble recovery. In the 2006 Music City Bowl against Clemson, he was used as a running back for one play and scored a one-yard touchdown.