Jaylon Smith was born on June 14, 1995, in Fort Wayne, Indiana. He is an inside linebacker in the NFL.
Smith attended Bishop Luers High School in Fort Wayne, Indiana, where he was a letterman in football, basketball and track. In football, he won the Butkus Award as a senior, given to the best high school linebacker in the country, and was named the Mr. Football award winner for the state of Indiana.
He helped Bishop Luers to 40–28 over Evansville Mater Dei in 2012 Indiana 2A title game while rushing for 150 yards and scoring three touchdowns, as Bishop Luers became first Indiana 2A school to win four straight state titles. He finished with 1,265 rushing yards and 18 TDs on 176 attempts as senior in 2012 to go with 10 receptions for 66 yards and two more TDs. Defensively, he recorded 72 tackles (43 solo), 19.5 tackles for loss, eight sacks, two forced fumbles, one fumble recovery and seven pass deflections.
Smith signed his letter of intent on February 6, 2013, and committed to attend and play football at the University of Notre Dame. He was considered the best outside linebacker recruit of his class by Rivals.com and Scout.com. He played in the 2013 U.S. Army All-American Bowl.
In 2013, Smith won the starting DOG linebacker position. Starting all 13 games, he recorded 67 tackles, including 6.5 for loss, one forced fumble, three pass breakups, and one interception. His best game came in a 34–30 victory against Arizona State, where he recorded nine tackles, including 1.5 for loss. He notched his first career interception against USC on a pass thrown by Cody Kessler.
With the arrival of new defensive coordinator Brian VanGorder, he was moved to an inside linebacker position in 2014. He was one of three players to start all 13 games on defense, recording 112 tackles, including nine for loss, and 3.5 sacks, adding two pass breakups and one forced fumble. He was named the FBS Independent Co-Defensive Player of the Year, along with teammate Joe Schmidt IV and was named a second-team All-American by the Associated Press.
During his junior year in 2015, Smith played in all 13 games with 115 tackles, nine tackles for loss, one sack, five passes defended, two fumble recoveries, and 1 forced fumble. He won the Butkus Award, given annually to college football's top linebacker. During the Fiesta Bowl game against Ohio State. It was confirmed that the knee was diagnosed with tears to the ACL and LCL. On January 11, 2016, Smith announced he would forego his remaining eligibility and enter the 2016 NFL draft.
The Dallas Cowboys selected Smith in the second round (34th overall) of the 2016 NFL Draft. The Cowboys selected Smith after they unsuccessfully tried to trade their second (34th overall) and third round (67th overall) draft choices to move back into the first round of the 2016 NFL Draft to select quarterback Paxton Lynch. Smith was operated on by the Dallas Cowboys’ doctor, Dan Cooper. Smith was the fourth linebacker drafted in 2016.
On May 20, 2016, the Dallas Cowboys signed Smith to a four-year, $6.49 million contract that includes $4.42 million guaranteed and a signing bonus of $2.92 million. On June 7, 2017, Smith participated in drills for the first time in front of media since his torn ACL and MCL. Smith entered training camp as a backup middle linebacker. On July 20, 2017, the Dallas Cowboys signed linebacker Justin Durant as insurance in the event Smith was unable to fully recover before the start of the regular season.
On July 26, 2017, Smith took part in practice in full pads for the first time since college, but received limited reps as the coaching staff was cautious as he became acclimated to playing in full pads. The Dallas Cowboys planned to use Smith as a backup and rotational player primarily on first and second down to avoid putting him in pass situations. The plan to use him for 25-30 snaps per game was eventually scrapped after they were forced to use him more than expected after starting middle linebacker Anthony Hitchens suffered a tibial plateau fracture in the last preseason game. Head coach Jason Garrett named Smith the starting middle linebacker to begin the regular season, alongside outside linebackers Sean Lee and Damien Wilson.
Smith entered training camp slated as the starting middle linebacker after Anthony Hitchens departed for the Kansas City Chiefs during free agency. Head coach Jason Garrett named Smith the starting middle linebacker to start the regular season, ahead of rookie first-round pick Leighton Vander Esch. He began the season alongside outside linebackers Sean Lee and Damien Wilson. On October 7, 2018, Smith collected 12 combined tackles (six solo), broke up a pass, and made a sack during a 19–16 loss at the Houston Texans in Week 5.
On October 5, 2021, the Cowboys released Smith after being passed on the depth chart by rookie Micah Parsons and Keanu Neal. He was shortly picked up by the Green Bay Packers after.
On September 20, 2022, Smith re-signed with the New York Giants to their practice squad. On October 1, 2022, he was promoted to the active roster.