Landry made an immediate impact at LSU in 2003, starting ten games as a true freshman in 2003 while helping the Tigers win the BCS National Championship.

[5] He was one of four LSU players taken in the first round of that draft, along with quarterback JaMarcus Russell, and wide receivers Dwayne Bowe and Craig Davis.

[6] Landry proved his worth throughout the year without collecting an interception during the regular season, though he was noted for having a problem with disregarding coverage and going for the big hit.

Taylor suffered an injury which kept him out of action in Week 11 and 12, and Landry was moved to the free safety position in his place.

Landry appeared in fifteen games for the Redskins and recorded his only interception in a victory over the Oakland Raiders in Week 14.

On December 15, 2011, Coach Mike Shanahan stated that he believed Landry "would’ve been defensive player of the year" for the 2010 season had he not been injured.

On December 15, he was officially placed on injured reserve after being advised to get surgery on his left Achilles tendon, ending the last season of his rookie contract having played a total of eight games.

[11] On January 23, 2012, it was announced that Landry had decided to go with alternative medicine, receiving the stem cell treatment known as AminoMatrix on his left Achilles tendon in hope of avoiding surgery.

[15] Landry reached an agreement with the New York Jets on March 19, 2012, on a one-year, $3.5 million contract with $700,000 in guaranteed money.

[18] With the bone still healing, he was placed on the physically unable to perform list prior to the start of training camp.

He made his presence known by making an impressive tackle against Fred Jackson, which took him out for the rest of the game, and forcing a fumble that was recovered by Yeremiah Bell.

[21] He had another good performance in Week 3 against the Miami Dolphins after intercepting Ryan Tannehill, he ran the ball back for 18 yards and scored his first career touchdown.

[24] By the end of the season, Landry set new career highs of 100 combined tackles and four forced fumbles, as well as recording two interceptions, eight pass deflections, and one touchdown.

[29] On November 24, 2015, Landry was suspended for testing positive for PEDs, his third such violation of the league's performance-enhancing drug policy.

[33] During his time with the Redskins, Landry's fans and teammates began calling him "Dirty 30" for his jersey number and aggressive playing style.