He played college football for the Indiana Hoosiers and was selected by the New Orleans Saints in the second round of the 2008 NFL draft.

Porter is best known for being a crucial player during the Saints’ 2009 season, in which he intercepted Brett Favre in the NFC Championship Game and then won Super Bowl XLIV over the Indianapolis Colts, sealing the game by famously intercepting Peyton Manning and returning it for a touchdown.

Porter attended Port Allen High School, where he played quarterback, running back, wide receiver, and cornerback.

He earned first team All-District 3A honors in his first year of organized football as a junior and second-team as a senior after recording 93 tackles, 11 interceptions (two returned for touchdowns) and 14 pass breakups.

In addition to football, Porter was also a starter at point guard for the basketball team and a sprinter on the track & field, where he posted a personal-best time of 10.4 seconds in the 100-meter dash.

At the conclusion of the pre-draft process, Porter was projected to a third round pick by NFL draft experts and scouts.

Midway through the fourth quarter of the NFC Championship game on January 24, 2010, with the Minnesota Vikings already in the red zone and driving towards a score, Porter punched the ball out of the hands of Vikings wide receiver Bernard Berrian; the fumble was recovered by the Saints.

However, prior to the Broncos' Week 6 game at the San Diego Chargers, he experienced aftereffects from a seizure that he suffered during the preseason.

[4][13] In a game against the New York Giants on November 10, 2013, he became the first player in NFL history to return an interception for a touchdown against both Peyton and Eli Manning.

[4][22][23] On April 10, 2017, Porter was released by the Bears after they had signed free agents Prince Amukamara and Marcus Cooper.