He played college football for the Texas Longhorns and was selected by the Buffalo Bills in the second round of the 2011 NFL draft.

As a junior in 2010, he started 11 games, missing two due to an injury, and recorded 45 tackles, one quarterback sack, and two forced fumbles.

[5] In 2015, Williams was injured in a Week 2 game against the New England Patriots while attempting a flying goal line tackle on Julian Edelman.

[6] In Week 7, Williams suffered another serious neck injury after a hit by Miami Dolphins wide receiver Jarvis Landry.

[9][10] His retirement came after multiple head and neck injuries throughout his career, citing it was the main concern of other teams not signing him after workouts in 2017, including the Jaguars, Texans, and Chiefs.