Smith played his entire professional career with the Jaguars, earning second-team All-Pro honors and a Pro Bowl selection in 2017.
[6] On January 21, 2014, it was announced that Smith would play in the 2014 Senior Bowl as part of Jacksonville Jaguars head coach Gus Bradley's South team.
[8] On March 18, 2014, he attended Florida State's pro day and performed the short shuttle, three-cone drill, and positional drills for scouts and team representatives from all 32 NFL teams, including head coaches Mike Tomlin (Pittsburgh Steelers), Chip Kelly (Philadelphia Eagles), Jim Caldwell (Detroit Lions), and Mike Zimmer (Minnesota Vikings).
[17] Throughout training camp, Smith competed against Geno Hayes, LaRoy Reynolds, and Dekoda Watson for a job as one of the starting outside linebackers.
[21] He made his professional regular season debut in the Jaguars' season-opener at the Philadelphia Eagles and recorded three combined tackles during a 34–17 loss.
The following week, Smith recorded five combined tackles and made his first career sack on quarterback Kirk Cousins as the Jaguars were routed at the Washington Redskins 41–10.
[22] On October 19, 2014, Smith collected four combined tackles, broke up two passes, and returned his first career interception off Brian Hoyer for 15-yards in a 24–6 victory against the Cleveland Browns.
[23] He finished his rookie season in 2014 with a total of 104 combined tackles (72 solo), four pass deflections, two sacks, a forced fumble, and an interception in 16 games and nine starts.
[28] Smith finished the 2016 season with a career-high 128 combined tackles (99 solo), seven pass deflections, 2.5 sacks, and an interception in 14 games and 14 starts.
On December 4, 2016, Smith made six solo tackles and sacked quarterback Trevor Siemian as the Jaguars lost 20–10 to the Denver Broncos.
[32] In Week 5, Smith recorded ten combined tackles, broke up a pass, and returned an interception by quarterback Ben Roethlisberger for a 28-yard touchdown in the Jaguars' 30–9 victory at the Pittsburgh Steelers.
[36] Smith finished the season with 102 combined tackles (76 solo), five pass deflections, three interceptions, one touchdown, and one sack in 14 games and 14 starts.
The following week, he made 16 combined tackles (14 solo), deflected a pass, and returned a fumble recovery by Ben Roethlisberger for a 50-yard touchdown during the second quarter of their 45–42 victory at the Steelers in the AFC Divisional Round.
On January 21, 2018, Smith recorded eight solo tackles and two pass deflections as the Jaguars lost the AFC Championship Game 24–20 at the New England Patriots.
On December 23, 2018, Smith recorded six combined tackles, deflected a pass, and returned an interception for the third touchdown of his career during a 17–7 win at the Dolphins in Week 16.
Smith intercepted a pass by Dolphins’ quarterback Ryan Tannehill, that was initially intended for running back Kalen Ballage, and returned it for a 33-yard touchdown during the fourth quarter.
[41] He started in all 16 games in 2018 and recorded a career-high 134 combined tackles (100 solo), two pass deflections, two interceptions, one sack, one forced fumble, and a touchdown.