He played college football for the University of Southern California (USC), and earned unanimous All-American honors.

While in high school Ellis played defensive tackle and fullback in goal line situations.

Ellis attended the University of Southern California, where he played for coach Pete Carroll's USC Trojans football team from 2003 to 2007.

He was first team coaches and Rivals.com All-Pac-10 conference, first-team College Football News All-American and won the Morris Trophy.

[2] At the end of the 2007 season, Ellis was voted the Pacific-10 Conference Defensive Player of the Year by league coaches, and was selected to the all-conference first team.

Initially, New Orleans attempted to trade up for LSU DT Glenn Dorsey, whom they had valued higher than Ellis.

On June 11, 2013, Ellis signed a one-year contract with the Chicago Bears,[13] a team that had a top five defense in yards and point-per-game allowed the year prior.

On July 25, 2013, Ellis did not report to training camp and advised the Bears of his intention to retire from the NFL.