He played college football for the Alabama Crimson Tide, earning unanimous All-American honors in 2009 and winning the 2010 BCS National Championship.
[4] He chose Alabama over offers from Auburn, Ole Miss, Mississippi State, Vanderbilt, Kentucky, and Louisville.
As a sophomore in 2008, McClain compiled 95 tackles, three sacks, and an interception, earning Associated Press (AP) third-team All-American honors, and was a first-team All-SEC selection.
He was named Football Writers Association of America (FWAA) National Defensive Player of the Week for his performance against Kentucky in early October.
[8][9] On January 11, 2010, a few days after winning the BCS National Championship, McClain decided to forgo his senior year at Alabama and enter the 2010 NFL Draft.
In week 2 of the 2010 season against the St. Louis Rams, McClain body slammed Danny Amendola, which drew an "unnecessary roughness" call and eventually a $5,000 fine by the NFL.
During a week 4 game against Denver, McClain played in 73 snaps, but following the bye, the Raiders made the decision to replace him with 4th round rookie Miles Burris in their nickel package, resulting in McClain playing only 17 snaps compared to Burris' 55 in the week 6 game against the Atlanta Falcons.
[16] According to sources within the Raiders, it was reported by NFL.com's Albert Breer and Ian Rapoport that McClain had been kicked out of an official team practice session on November 29 due to an "incident".
McClain had been drafted with the hopes that he could help improve the Raiders' run defense, an area where the team had been consistently among the worst in the league.
Following a string of poor first round picks by late owner/GM Al Davis, the selection of McClain was applauded by many analysts.
The trade paid off, with McClain becoming an unquestioned team leader and playing a critical role in the resurgence of the Cowboys' previously suspect defense.
Although he was slowed down with groin and knee injuries after week 9 of the season, the unit raised its level when he was healthy and was setting the tone with his physical style and play-making ability.
On July 2, the NFL announced that he would be suspended for the first four games of the 2015 season for violating the league's substance abuse policy.
[27] He also had a surprise knee surgery during the offseason, which forced him to miss the entire conditioning program and most of training camp.
[30][31] On August 2, it was reported that McClain had become addicted to codeine after consuming the mixture known as purple drank, and that he is "a long way from ever resuming his NFL career".
His estranged father was granted custody but McClain left to return to Decatur to stay eligible for football.
[41] Between his departure from the Ravens in May 2013 and his return to football with the Cowboys in July 2014, McClain moved to Tuscaloosa, where he re-enrolled at the University of Alabama to try to finish his bachelor's degree in family financial planning.
[43] On December 1, 2011, McClain was arrested by Decatur police and charged with third-degree assault, menacing, reckless endangerment, and discharging a firearm inside the city limits, all of which are misdemeanors, for a shooting incident that occurred the night before.
[47] On January 8, 2013, he was arrested by Decatur Police in Morgan County after an officer pulled him over for a window tint violation.
On August 2, 2016, after his suspension in June 2016 for violating the NFL substance abuse policy, it was reported that McClain had become addicted to codeine after consuming the mixture known as purple drank.