He played college football for the Louisiana Tech Bulldogs, and was signed by the Houston Texans as an undrafted free agent in 2006.

[4][5] Throughout training camp, Williams competed for a roster spot as a backup cornerback and special teams player against Kevin Garrett, Von Hutchins, Derrick Johnson, and Earthwind Moreland.

[10] During training camp, Williams competed for a job as a backup cornerback against Jarrett Bush, Patrick Dendy, Frank Walker, Will Blackmon, and Antonio Malone.

[11] Head coach Mike McCarthy named Williams the sixth cornerback on the depth chart to begin the regular season, behind Al Harris, Charles Woodson, Jarrett Bush, Frank Walker, and Will Blackmon.

[12] On September 9, 2007, Williams made his professional regular season debut in the Green Bay Packers' season-opener against the Philadelphia Eagles and returned four kickoffs for a total of 100-yards in their 17–16 victory.

[13] On November 22, 2007, Williams recorded a season-high four solo tackles and two pass deflections during a 47–36 victory at the Detroit Lions in Week 12.

[18] The Green Bay Packers finished the 2007 NFL season first in the NFC North with a 13–3 record and received home–field advantage and a first–round bye.

On January 12, 2008, Williams appeared in the first career playoff game and made four solo tackles and a pass deflection during a 42–20 win against the Seattle Seahawks in the NFC Divisional Round.

[14] On January 20, 2007, he made two solo tackles, broke up a pass, and recovered a fumble as the Packers lost 23–20 to the New York Giants, who eventually won Super Bowl XLII, in the NFC Championship.

[21] On October 12, 2008, Williams made a solo tackle, broke up a pass, and an interception in a 27–17 win at the Seattle Seahawks in Week 6.

He entered training camp slated to return as the third cornerback on the Packers' depth chart ahead of Will Blackmon, Jarrett Bush, and Josh Bell.

[23] He began the 2009 NFL season as the third cornerback on the depth chart, behind cemented starters Charles Woodson and Al Harris.

[27] In Week 14, Williams recorded six solo tackles and made his first career sack for an eight–yard loss on Jay Cutler during a 21–14 victory at the Chicago Bears.

[5][30] He entered training camp slated as a starting cornerback as Al Harris was still recovering from his injury and was placed on the PUP list for the first six games before being released midseason.

[32] Special teams coordinator Shawn Slocum also named him the second punt returner on the depth chart behind Will Blackmon.

On September 12, 2010, Williams started in the Green Bay Packers' season–opener at the Philadelphia Eagles and made three solo tackles and a season–high three pass deflections during a 27–20 victory.

On October 17, 2010, he collected a season-high eight combined tackles (seven solo), broke up a pass, and made an interception during a 23–20 loss to the Miami Dolphins in Week 6.

He started all 16 games for the first time in his career and recorded 57 combined tackles (50 solo), 20 pass deflections, and a career-high six interceptions.

[18] The Green Bay Packers finished the 2010 NFL season second in the NFC North with a 10–6 record, clinching a wildcard position.

[33] On January 20, 2011, Williams was added to the 2011 Pro Bowl roster as a reserve in place of Philadelphia Eagles cornerback Asante Samuel, who pulled out due to an injury.

On September 8, 2011, he started in the Green Bay Packers' home–opener against the New Orleans Saints and made three solo tackles before exiting in the third quarter of a 42–34 victory after injuring his shoulder.

On January 1, 2012, Williams tied his season-high of nine combined tackles (seven solo) and deflected two passes during a 45–41 win against the Detroit Lions in Week 17.

1 starting cornerback, and saw competition for his spot from Sam Shields, Casey Hayward, Davon House, Micah Hyde, and Jarrett Bush.

[38] Head coach Mike McCarthy chose Williams and Sam Shields as the starting cornerbacks to kick off the regular season.

[18] The Green Bay Packers finished the 2013 NFL season first in the NFC North with an 8–7–1 record, clinching a playoff berth.

Williams and Sam Shields returned as the Green Bay Packers' starting cornerback duo for the third consecutive season.

[47] On November 1, 2015, Williams recorded a season-high nine combined tackles and a pass deflection during a 34–20 loss to the Arizona Cardinals in Week 8.

[49] On January 4, 2016, the Cleveland Browns fired head coach Mike Pettine and general manager Ray Farmer after they finished with a 3–13 record.

Head coach Hue Jackson named Williams the third cornerback on the depth chart to start the regular season, behind Joe Haden and Jamar Taylor, and the first-team nickelback.

Head coach Bruce Arians named him the third cornerback on the depth chart to start the 2017 regular season, behind Patrick Peterson and Justin Bethel.