As a true freshman, he appeared in 11 games as a backup defensive end, tallying 16 tackles and 3.5 sacks (third on the team).

He made 4 tackles (3 for loss), 2 sacks and one forced fumble in the 2009 Cotton Bowl Classic against the University of Mississippi.

Williams was selected by the Dallas Cowboys in the fourth round (120th overall) of the 2009 NFL draft,[5] with the plan of converting him into an outside linebacker on their 3-4 defense.

He tore his left ACL in the second preseason game while playing special teams and was placed on the injured reserve list on September 1.

[6] In his second season, he played tentatively coming back from injury and was declared inactive in 10 games.