Dennard excelled on both sides of the ball at Wilcox County High School, and was Nebraska's first scholarship player from Georgia since 2001.

[6] Sources: Coming out of Nebraska, Dennard was projected to go as high as the first round, but was typically considered to be a second to fourth-round pick by the majority of NFL draft experts and scouts.

[11] He attended the NFL combine, and was unable to perform the bench press, three-cone drill, and short shuttle due to a hip and shoulder injury.

On March 8, 2012, Dennard opted to participate at Nebraska's pro day, along with Jared Crick, Lavonte David, Jermarcus Hardrick and Marcel Jones.

[19] He competed with Devin McCourty, Kyle Arrington, Ras-I Dowling, Will Allen, and Sterling Moore throughout training camp for the job as the starting cornerback while Aqib Talib served his four-game suspension to begin the season.

Dennard suffered a hamstring injury and missed a bulk of training camp, but returned for the last preseason game.

[20] Head coach Bill Belichick named Dennard the fifth cornerback on the Patriots' depth chart to begin the 2012 season, behind McCourty, Arrington, Dowling, and Moore.

He finished his rookie season with 35 combined tackles (34 solo), eight pass deflections, three interceptions, and a touchdown in ten games and seven starts.

On January 13, 2013, Dennard started his first career playoff game and recorded three combined tackles and a forced fumble during the 41–28 victory over the Houston Texans.

[25] Dennard returned to the New England Patriots' training camp and competed with Ras-I Dowling, Kyle Arrington, and Logan Ryan for the starting cornerback role.

[26] He started the New England Patriots' season-opener against the Buffalo Bills and collected three solo tackles and a pass deflection in their 23-21 victory.

The following game, he collected three solo tackles as the Patriots' were eliminated from the playoffs after losing 26-16 to the Denver Broncos in the AFC Championship.

He entered training camp in 2014 and faced stiff competition from Darrelle Revis, Kyle Arrington, Brandon Browner, and Logan Ryan for the vacant starting cornerback job left after the departure of Aqib Talib.

After having minimal playing time is Weeks 12-13, Dennard missed the remainder of the season with a hamstring injury, including the playoffs and Super Bowl XLIX.

[25] The New England Patriots finished the 2014 season atop the AFC East with a 12–4 record and went on to defeat the Indianapolis Colts 45–7 and then had a 28–24 win over the defending Super Bowl champion Seattle Seahawks.

They opted to waive Dennard even though they lost Darrelle Revis, Brandon Browner, and Kyle Arrington in free agency.

[44] On March 1, 2014, Dennard reported to the Lancaster County Adult Detention Facility in Nebraska to begin serving his 60-day jail term.

[46] On December 15, 2015, it was reported that Dennard had spent five days in Lancaster County Jail after violating the terms of his probation the week prior.