As a true freshman at Georgia in 2012, Jenkins played in 14 games and made six starts at outside linebacker. He recorded 31 tackles and five sacks. As a 13-game starter his sophomore year in 2013, Jenkins had 45 tackles and five sacks. Jenkins again started all 13 games his junior year in 2014, recording 70 tackles and five sacks. After he considered entering the 2015 NFL Draft, Jenkins announced that he would return for his senior year.
Professional career
Coming out of Georgia, Jenkins was considered one of the top linebacker prospects and received an invitation to the NFL combine. He attended the combine and completed the majority of drills until he suffered a hamstring injury that made him unable to perform the short shuttle and three-cone drill. Coincidentally, teammate Leonard Floyd also injured his hamstring at the combine and was unable to perform the three-cone and short shuttle. On March 16, 2016, he opted to participate at Georgia's pro day, along with Leonard Floyd, Malcolm Mitchell, John Theus, Keith Marshall, Marshall Morgan, Sterling Bailey, Quayvon Hicks, and ten other players. Jenkins completed the short shuttle and three-cone drill, while also running positional drills and lowering his time in the 40-yard dash. He also elevated his vertical to 38" and increased his number of reps on the bench press to 19. He was projected to be a third round pick by the majority of NFL draft experts and scouts. After he completed the pre-draft process, Jenkins was ranked as the eighth best linebacker prospect in the draft by NFL analyst Mike Mayock, the ninth best outside linebacker by NFLDraftScout.com, the ninth best linebacker by ESPN, and was ranked the 11th best linebacker by Sports Illustrated. Jenkins was drafted by the New York Jets in the third round in the 2016 NFL Draft. Jenkins was the second linebacker drafted by the Jets in 2016 behind Darron Lee and was the ninth linebacker selected in the entire draft. Fellow Georgia linebacker and teammate, Leonard Floyd, was selected in the first round by the Chicago Bears.
2016
He competed with Trevor Reilly, Lorenzo Mauldin, and Deion Barnes throughout training camp for the one of the jobs as starting outside linebacker. Head coachTodd Bowles named him one of the starting outside linebackers to start the season, opposite Lorenzo Mauldin. He suffered a calf injury in mid-August and was unable to play in the first two games of the season. On September 25, 2016, Jenkins made his professional regular season debut and first career start, recording five combined tackles in a 24–3 loss to the Kansas City Chiefs. During a Week 14 matchup against the San Francisco 49ers, he recorded four combined tackles and was credited with a half a sack on Colin Kaepernick in the Jets' 23–17 overtime victory. The next game, Jenkins collected five combined tackles and made his first career solo sack on Miami Dolphins' quarterback Matt Moore, as the Jets lost 34–13. Jenkins finished the season with 41 combined tackles, 2.5 sacks, a forced fumble and two passes defensed in 11 starts and 14 games.
2017
Jenkins returned as the de facto outside linebacker under Todd Bowles to start the season. In the New York Jets' season-opener at the Buffalo Bills, Jenkins recorded a season-high four solo tackles in the Jets' 12–21 loss. On November 2, 2017, he earned two solo tackles, sacked Buffalo Bills' quarterback Tyrod Taylor twice, and forced the first fumble of his career, as the Jets won 34–21 on Thursday Night Football. He was named the AFC Defensive Player of the Week for his performance in Week 9.
2020
Jenkins re-signed with the Jets on April 23, 2020.
