He played college football for the Ohio State Buckeyes, and was selected by the Buffalo Bills with the eighth overall pick in the 2006 NFL draft.

Whitner also played in the NFL for the San Francisco 49ers, Cleveland Browns, and Washington Redskins.

After his senior high school football season he was invited to the U.S. Army All-American Bowl game.

His junior year proved his most rewarding as he earned all-conference honors and helped the Buckeyes defeat Notre Dame during the 2005 Fiesta Bowl.

[10] In 2009, Whitner recorded his first career touchdown on a 76-yard interception return from Tampa Bay Buccaneers quarterback Byron Leftwich in Week 2.

His most productive game to date was in Week 12 of the 2010 season, where he recorded 18 total tackles against the Pittsburgh Steelers.

After previously announcing on Twitter that he would be going to the Cincinnati Bengals, he changed his mind and signed with San Francisco.

[12] During the 2011 playoffs, Whitner became famous for making vicious hits like against New Orleans Saints running back Pierre Thomas as he was driving for a touchdown.