Johnson played college football at the University of Alabama, where he was a member of the 2009 National Championship team.
Johnson played for Booker High School in Sarasota, Florida, leading his team to a 13-2 record as a senior, had five interceptions, 15 pass breakups and 39 solo tackles.
He was a three-sport star, playing on a state-champion basketball team in addition to competing in the triple jump in the Florida state track & field championships.
In 2008, as a junior, Johnson served as Alabama's third cornerback in nickel and dime defensive packages.
In 2007, he played in nine games as a back-up in the secondary and had four tackles, one pass breakup and a fumble recovery on the season.