2019 season Simmons was drafted by the
Tennessee Titans in the first round (19th overall) of the
2019 NFL draft. On May 22, 2019, he signed a four-year, $12.66 million rookie contract with a team option for a fifth year with a $7.23 million signing bonus. Simmons was placed on the reserve/non-football injury list to start the 2019 season while recovering from his torn ACL. On October 19, 2019, the Titans activated Simmons from the non-football injury list. He made his NFL debut the next day against the
Los Angeles Chargers and finished the 23–20 victory with four tackles and his first NFL sack on
Philip Rivers. During Week 14 against the
Oakland Raiders, Simmons had five tackles and a sack in the 42–21 road victory. In the next game against the
Houston Texans, he recorded three tackles and a pass deflection during the 24–21 loss. Simmons finished his rookie year with 32 tackles, two sacks, and a pass deflection in nine games and seven starts. The Titans finished second in the
AFC South with a 9–7 record and qualified for the playoffs as the #6-seed. In the Wild Card Round against the
New England Patriots, Simmons made his postseason debut and finished the 20–13 road victory with a solo tackle. During the Divisional Round against the Ravens, Simmons had two tackles and recovered a fumble forced by teammate
Jurrell Casey on
Lamar Jackson in the 28–12 road victory. However, the Titans lost to the eventual Super Bowl champions, the
Kansas City Chiefs, in the AFC Championship Game, with Simmons recording no statistics during the 35–24 road loss.
2020 season During the season-opener against the
Denver Broncos on
Monday Night Football, Simmons recorded four tackles and a fumble recovery in the narrow 16–14 road victory. In the next game against the
Jacksonville Jaguars, he had three tackles and a pass deflection during the 33–30 victory. The following week against the
Minnesota Vikings, Simmons recorded five tackles and his first sack of the season on
Kirk Cousins in the narrow 31–30 road victory. Simmons was placed on the reserve/
COVID-19 list by the team on October 3. He was activated on October 15. Simmons returned in time for the Week 6 matchup against the Texans and finished the 42–36 overtime victory with six tackles and a sack. In the next game against the
Pittsburgh Steelers, Simmons recorded three tackles and a pass deflection during the 27–24 loss. Two weeks later against the
Chicago Bears, he had three tackles, a pass deflection, a fumble recovery, and forced a fumble on running back
David Montgomery that was recovered and returned by teammate
Desmond King for a 63-yard touchdown in the 24–17 victory. Simmons was named AFC Defensive Player of the Week for his performance in Week 9. During a Week 10 34–17 loss to the
Indianapolis Colts on
Thursday Night Football, Simmons recorded two tackles and a pass deflection. Two weeks later against the Colts, he had four tackles, a sack, and a pass deflection in the 45–26 road victory. During Week 15 against the
Detroit Lions, Simmons recorded two tackles and a fumble recovery in the 46–25 victory. Simmons finished his second professional season with 49 tackles, three sacks, five pass deflections, a forced fumble, and three fumble recoveries in 15 games and starts. The Titans finished atop the AFC South with an 11–5 record and qualified for the playoffs. During the Wild Card Round against the Ravens, Simmons had three tackles in the 20–13 loss. He was ranked 78th by his fellow players on the
NFL Top 100 Players of 2021.
2021 season During the season-opening 38–13 loss to the
Arizona Cardinals, Simmons had five tackles and his first sack of the season on
Kyler Murray. In the next game against the
Seattle Seahawks, Simmons recorded a tackle and 0.5 sacks during the 33–30 overtime road victory. The following week against the Colts, he had three tackles and a pass deflection in the 25–16 victory. During Week 5 against the Jaguars, Simmons recorded three tackles and a pass deflection in the 37–19 road victory. In the next game against the
Buffalo Bills on
Monday Night Football, he had five tackles and a sack during the 34–31 victory. Three weeks later against the
Los Angeles Rams on
Sunday Night Football, Simmons recorded a season-high six tackles and sacked
Matthew Stafford thrice in the 28–16 road victory. During a narrow Week 10 23–21 victory over the
New Orleans Saints, Simmons had four tackles, a pass deflection, and sacked
Trevor Siemian twice. In the next game against the Texans, Simmons recorded five tackles and a pass deflection during the 22–13 loss. The following week against the Patriots, he tied his season-high of six tackles in the 36–13 road loss. Following a Week 13 bye, the Titans returned home to face the Jaguars. Simmons finished the 20–0 shutout victory with three tackles and a pass deflection. In the next game against the Steelers, he had a tackle and a pass deflection during the 19–13 road loss. During the regular season finale against the Texans, Simmons recorded two tackles and a sack in the 28–25 road victory. Simmons finished the 2021 season with 54 tackles, 8.5 sacks, and six pass deflections in 17 games and starts. The Titans finished atop the AFC South with a 12–5 record and qualified for the playoffs as the #1-seed. In the Divisional Round against the
Cincinnati Bengals, Simmons had eight tackles and sacked
Joe Burrow thrice during the 19–16 loss. On January 31, 2022, Simmons was named to his first
Pro Bowl as an injury replacement to
Chris Jones. Simmons was ranked 54th by his fellow players on the
NFL Top 100 Players of 2022.
2022 season On April 27, 2022, the Titans picked up the fifth-year option on Simmons' contract. During the season-opener against the
New York Giants, Simmons had six tackles and sacked
Daniel Jones twice (one was a strip-sack) in the narrow 21–20 loss. In the next game against the Bills on Monday Night Football, Simmons recorded a pass deflection during the 41–7 road loss. The following week against the
Las Vegas Raiders, he had two tackles and a pass deflection in the narrow 24–22 victory. During a Week 5 21–17 road victory over the
Washington Commanders, Simmons recorded five tackles and 1.5 sacks. Following a Week 6 bye, the Titans returned home to face the Colts. Simmons finished the 19–10 victory with six tackles and sacked
Matt Ryan once. In the next game against the Texans, Simmons had two tackles and a sack during the 17–10 road victory. During Week 10 against the Chiefs on
Sunday Night Football, Simmons had four tackles and a pass deflection in the 20–17 overtime road loss. However, he missed the next game against the Broncos with an ankle injury. Simmons returned the following week against the
Green Bay Packers on
Thursday Night Football and recorded five tackles and sacked
Aaron Rodgers once in the 27–17 victory. During a Week 13 35–10 road loss to the
Philadelphia Eagles, Simmons recorded a tackle and a pass deflection. In the next game against the Jaguars, he had two pass deflections during the 36–22 loss. The following week against the Chargers, Simmons recorded a season-high seven tackles and sacked
Justin Herbert once in the 17–14 road loss. Simmons finished the 2022 season with 54 tackles, 7.5 sacks, seven pass deflections, and a forced fumble in 15 games and starts. He was named to his second Pro Bowl. Simmons was ranked 58th by his fellow players on the
NFL Top 100 Players of 2023.
2023 season On April 7, 2023, Simmons signed a four-year, $94 million contract extension with the Titans. During the narrow season-opening 16–15 road loss to the Saints, Simmons recorded five tackles and his first sack of the season on
Derek Carr. In the next game against the Chargers, Simmons once again had five tackles and a sack during the 27–24 overtime victory. Two weeks later against the Bengals, he recorded two tackles and 0.5 sacks in the 27–3 blowout victory. During Week 8 against the
Atlanta Falcons, Simmons had five tackles and sacked
Desmond Ridder twice (one was a strip sack) in the 28–23 victory. In the next game against the Steelers on
Thursday Night Football, Simmons recorded a season-high seven tackles during the 20–16 road loss. The following week against the
Tampa Bay Buccaneers, he had four tackles and a pass deflection in the 20–6 road loss. During a Week 11 34–14 road loss to the Jaguars, Simmons recorded two tackles scored his first NFL career touchdown on a two-yard reception from quarterback
Will Levis after being declared an eligible receiver. In the next game against the
Carolina Panthers, Simmons had five tackles, a sack, and a fumble recovery during the 17–10 victory. On December 23, Simmons was placed on season-ending injured reserve. He finished the 2023 season with 44 tackles, 5.5 sacks, a pass deflection, a forced fumble, and a fumble recovery to go along with a receiving touchdown in 12 games and starts. Simmons was ranked 73rd by his fellow players on the
NFL Top 100 Players of 2024.
2024 season During Week 3 against the Packers, Simmons had five tackles and his first sack of the season on
Malik Willis in the 30–14 loss. However, Simmons missed the next game due to an elbow injury. During a Week 7 34–10 road loss to the Bills, Simmons recorded two tackles and a pass deflection. In the next game against the Lions, he had four tackles, a sack, and a forced fumble during the 52–14 road loss. The following week against the Patriots, Simmons recorded five tackles and a fumble recovery in the 20–17 overtime victory. During Week 10 against the Chargers, Simmons had five tackles and a pass deflection in the 27–17 road loss. In the next game against the Vikings, he recorded four tackles, a forced fumble, and a fumble recovery during the 23–13 loss. The following week against the Texans, Simmons had two tackles, a sack, and a pass deflection in the 32–27 road victory. During a Week 13 42–19 road loss to the Commanders, Simmons recorded a season-high nine tackles. In the next game against the Jaguars, he had five tackles and a pass deflection during the 10–6 loss. Two weeks later against the Colts, Simmons tied his season-high of nine tackles and sacked
Anthony Richardson once in the 38–30 road loss. Simmons finished the 2024 season with a career-high 76 tackles, five sacks, two forced fumbles, and four pass deflections in 16 games and starts. He earned his third
Pro Bowl nomination as a replacement for injured defensive tackle
Nnamdi Madubuike.
2025 season During the season-opening 20–12 road loss to the Broncos, Simmons recorded four tackles and strip-sacked
Bo Nix once. Three weeks later against the Texans, Simmons had five tackles and a sack in the 26–0 shutout road loss. In the next game against the Cardinals, he recorded a season-high eight tackles and 1.5 sacks during the narrow 22–21 road victory. During Week 6 against the Raiders, Simmons had six tackles and a sack in the 20–10 road loss. He did not play in Weeks 8 and 9 due to a hamstring injury. Simmons returned in time for the Week 11 matchup against the Texans and finished the 16–13 loss with three tackles and a sack. During a Week 13 25–3 loss to the Jaguars, Simmons recorded six tackles and a sack. In the next game against the
Cleveland Browns, he had seven tackles, 1.5 sacks, and a pass deflection during the narrow 31–29 road victory. The following week against the
San Francisco 49ers, Simmons recorded seven tackles and strip-sacked
Brock Purdy once while also scoring his second career touchdown on a one-yard reception from quarterback
Cam Ward in the 37–24 road loss. During Week 16 against the Chiefs, Simmons had three tackles and a pass deflection in the 26–9 victory. In the next game against the Saints, he recorded seven tackles and strip-sacked
Tyler Shough during the 34–26 loss. During the regular season finale against the Jaguars, Simmons had two tackles and a sack in the 41–7 road loss. Simmons finished the 2025 season with 67 tackles, 11 sacks, three forced fumbles, and three pass deflections to go along with a touchdown reception in 15 games and starts. He was named to his fourth Pro Bowl and was also named first-team All-Pro. ==Career statistics==