He played college football for the Penn State Nittany Lions and was selected with the second overall pick by the Washington Redskins of the 2000 NFL draft.

On a fourth and short yardage play, Arrington anticipated the snap count and jumped over the offensive line to tackle the runner in the backfield.

[6] Arrington's tendency for spectacular plays and his cover appearance on the Sports Illustrated 1999 College Football Preview Issue led many to mention him as a possible Heisman Trophy candidate.

On December 11, 2014, the Big Ten Network included Arrington on "The Mount Rushmore of Penn State Football", as chosen by online fan voting.

His agent Carl Poston was accused of neglecting to inspect the final revision of the contract, in which $6.5 million worth of bonuses contained in earlier drafts were missing.

[12] Arrington's final two seasons with the Redskins was marred by knee injuries and conflicts with coaches Joe Gibbs and Gregg Williams.

He was issued two citations, one for failure to control speed to avoid a collision, the other for operating a vehicle without a class license that contributed to a crash.

[16] Arrington started working on pregame and postgame shows for Comcast SportsNet before the Redskins' 2007 season week 3 loss to the Giants.

He returned to Comcast SportsNet's on-air lineup for week 3 of the 2008 NFL season, appearing on the pregame and postgame shows, and on Washington Post Live.

Comcast also featured a segment entitled "Life on the Sidelines with LaVar Arrington" during its Redskins Kickoff program on game days.

The firm's first clients were 2009 NFL draft prospects Aaron Maybin, Derrick Williams, Josh Gaines, and Tyrell Sales.

[27] Arrington appeared in several television commercials for Eastern Motors with fellow athletes Carmelo Anthony, Clinton Portis, Sean Taylor, and Antawn Jamison.