He played college football for the North Alabama Lions and Florida Gators and was selected by the St. Louis Rams in the second round of the 2012 NFL draft.

Jenkins had his most success as a member of the New York Giants, who he played four seasons with and made a Pro Bowl, and also had stints with the New Orleans Saints, Tennessee Titans and San Francisco 49ers.

On March 9, 2012, he participated at North Alabama's pro day and opted to only perform positional drills for team representatives and scouts.

Scouts cited Jenkins' past personal off the field issues, small stature, and possible ability to adapt to the physicality of the pro game as concerns and liabilities.

[14] Jenkins competed with fellow rookie Trumaine Johnson, veteran Cortland Finnegan, and Bradley Fletcher for the Rams' starting cornerback job throughout training camp.

[17] In Week 12 against the Arizona Cardinals, Jenkins collected two solo tackles and returned two interceptions for touchdowns after picking off fellow rookie Ryan Lindley.

[19] Jenkins finished his rookie season with a total of 73 combined tackles (64 solo), 14 pass deflections, four interceptions, and four touchdowns in 15 games and 14 starts.

[31] He finished the 2014 season with 59 combined tackles (55 solo), five pass deflections, a forced fumble, two interceptions, and two touchdowns in 14 games and 13 starts.

[33] On September 27, 2015, Jenkins made a season-high nine combined tackles, a pass deflection, and intercepted Pittsburgh Steelers' quarterback Ben Roethlisberger during a 12–6 loss.

[35] In Week 12, Jenkins had three solo tackles, a pass deflection, and an interception of Andy Dalton, as the Rams lost to the Cincinnati Bengals, 31–7.

[36] He finished his final season with the St. Louis Rams with a total of 64 combined tackles (56 solo), 16 pass deflections, and three interceptions in 15 games and 15 starts.

[41] Jenkins was the New York Giants' de facto starting cornerback to begin the regular season, joining a highly touted defensive back field featuring the likes of Dominique Rodgers-Cromartie, Eli Apple, and Landon Collins.

[42] The following week, he recorded a season-high eight combined tackles and two pass deflections against the New Orleans Saints, while also returning a blocked field goal for a Giants' touchdown.

[44] On October 9, 2016, Jenkins intercepted Green Bay Packers' quarterback Aaron Rodgers twice, made two tackles and had three pass deflections.

[48] On January 8, 2017, he played in his first career playoff game, making only one tackle during the Giants' 38–13 loss to the Green Bay Packers in the Wild Card Round.

[52] On October 15, 2017, Jenkins made five combined tackles and intercepted Denver Broncos' quarterback Trevor Siemian, returning it for a 43-yard touchdown in a 23–10 win.

[69] In the NFC Wild Card Round against the Minnesota Vikings, Jenkins recorded eight tackles and forced a fumble on wide receiver Adam Thielen which was recovered by teammate Vonn Bell during the 26–20 overtime loss.

[71] In Week 1 against the Tampa Bay Buccaneers, Jenkins recorded his first interception of the season off a pass thrown by Tom Brady and returned it for a 36-yard pick six during the 34–23 win.

[72] In Week 11 against the Atlanta Falcons, Jenkins intercepted a pass thrown by Matt Ryan in the fourth quarter to help secure a 24–9 win.

[82] On June 26, 2018, a dead body was found in the basement of Jenkins' New Jersey home, identified as a family friend who had been living at the house.