At linebacker, he set a school record with 158 tackles as a junior, and earned all-state honors from the Detroit Free Press as a senior, and he also contributed as a fullback.

Harris also participated in track and field, and this combination of size and speed led him to become one of the state's top prospects.

In 2006, he earned All-Big Ten Conference honors, was Wolverines co-MVP with Mike Hart, and was a second-team All-America selection by the Associated Press, Sports Illustrated, and Rivals.com.

[6] Throughout training camp, Harris competed against veterans Eric Barton and Victor Hobson for a job as a starting linebacker.

[8] On October 28, 2007, Harris recorded his first NFL start, making 17 tackles (10 solo) and 1 sack in Week 8 against the Buffalo Bills.

[9] For the 2007 NFL season, Harris had 127 tackles, 5 sacks, and two forced fumbles despite only starting 9 games, and earned various all-rookie honors.

Against the Houston Texans in the first week of the season, Harris finished with 11 tackles (six solo), one sack, and a deflected pass as the defense pitched a shutout.

In week three, as his team was only up seven points, he intercepted a Kerry Collins pass, and then followed that drive by sacking him on first down during the Tennessee Titans next series.

On January 16, 2011, Harris recorded his first career postseason interception in which he returned it for 58 yards against the New England Patriots in the AFC Divisional Round.

The Jets finished the season 11–5, clinching another wild card spot, and made it to the AFC Championship for the 2nd year in a row, but lost 19–24 against the Pittsburgh Steelers.

Harris finished the 2013 season with 124 combined tackles, 2 sacks, one passes defended and one forced fumble.