Jackson entered training camp in 2011 competing with Johnathan Joseph, Jason Allen, and Brice McCain to keep the starting cornerback position.
New defensive coordinator Wade Phillips named Jackson the left cornerback to start the regular season opposite Joseph.

Jackson started the Houston Texans' season opener against the Indianapolis Colts and made one tackle as the Texans routed the Colts, 34–7.
The following week, he was demoted to backup as Jason Allen was given the start.
During this time Allen showed good coverage, played well, and made a game-sealing interception in a 17-10 victory over the Pittsburgh Steelers in Week 4, which Jackson was inactive for.
However, he reclaimed his starting position in Week 6.
He finished the game with four solo tackles in a 29-14 loss to the Baltimore Ravens.
On November 6, 2011, Jackson recorded a season-high six solo tackles and a pass deflection in a 30-12 victory over the Cleveland Browns.
On December 4, 2011, he made three solo tackles and two pass reflections, and intercepted Matt Ryan for his first and only interception of the season in a 17-10 win over the Atlanta Falcons.
He finished with 42 combined tackles (37 solo), a forced fumble, an interception, and six deflected passes in 15 games and 13 starts.

The Houston Texans finished the 2011 season with a 10-6 record and received a playoff berth.
On January 7, 2012, Jackson appeared in his first career postseason game and made four combined tackles in a 31–10 victory over the Cincinnati Bengals in the AFC Wildcard Game.
The next game, he recorded four solo tackles and deflected a pass in a 20–13 loss to the Baltimore Ravens in the divisional playoff game.
Jackson received a coverage rating of -9.5 from PFF and was ranked 67th (45%) in success rate among qualified corners by Football Outsiders.
Jackson entered training camp in 2011 competing with Johnathan Joseph, Jason Allen, and Brice McCain to keep the starting cornerback position. New defensive coordinator Wade Phillips named Jackson the left cornerback to start the regular season opposite Joseph.
Jackson started the Houston Texans' season opener against the Indianapolis Colts and made one tackle as the Texans routed the Colts, 34–7. The following week, he was demoted to backup as Jason Allen was given the start. During this time Allen showed good coverage, played well, and made a game-sealing interception in a 17-10 victory over the Pittsburgh Steelers in Week 4, which Jackson was inactive for. However, he reclaimed his starting position in Week 6. He finished the game with four solo tackles in a 29-14 loss to the Baltimore Ravens. On November 6, 2011, Jackson recorded a season-high six solo tackles and a pass deflection in a 30-12 victory over the Cleveland Browns. On December 4, 2011, he made three solo tackles and two pass reflections, and intercepted Matt Ryan for his first and only interception of the season in a 17-10 win over the Atlanta Falcons. He finished with 42 combined tackles (37 solo), a forced fumble, an interception, and six deflected passes in 15 games and 13 starts.
The Houston Texans finished the 2011 season with a 10-6 record and received a playoff berth. On January 7, 2012, Jackson appeared in his first career postseason game and made four combined tackles in a 31–10 victory over the Cincinnati Bengals in the AFC Wildcard Game. The next game, he recorded four solo tackles and deflected a pass in a 20–13 loss to the Baltimore Ravens in the divisional playoff game. Jackson received a coverage rating of -9.5 from PFF and was ranked 67th (45%) in success rate among qualified corners by Football Outsiders.
Kareem Jackson