On November 12, 2009, Jackson and fellow freshmen teammates Mike Edwards and Nu'Keese Richardson were charged after an armed robbery attempt at a Pilot station on Cumberland Avenue in Knoxville, Tennessee. Less than two weeks later, charges against Jackson were dropped because a police investigation found that he had no prior knowledge of the alleged attempted robbery. On November 24, he was reinstated to the Tennessee football team.
After recording 37 tackles, a sack, an interception, a forced fumble and a fumble recovery, Jackson was named to Rivals.com's 2009 SEC All-Freshman Team for his standout play.
As a sophomore in 2010, Jackson started all 12 regular season games and compiled 65 tackles, 4 tackles for loss, a sack, 9 passes defended and 4 interceptions and was named to the All-SEC second team voted by the league's coaches.
On August 24, 2011, the University of Tennessee announced that Janzen Jackson was released from the football team for unspecified reasons. On August 28 Jackson is enrolled at the FCS McNeese State University Cowboys, where his father Lance Guidry played and coached.