Thomas accepted a football scholarship from South Carolina State University. As a redshirt freshman, he played in 11 out of 12 games, contributing mainly on special teams, while posting 17 tackles, one pass defensed and a fumble recovery. As a sophomore, he started 11 games at outside linebacker, recording 100 tackles, 5 tackles for loss, 2.5 sacks, 3 interceptions and a fumble recovery. He was named the team’s defensive MVP at the end of the season. In his first career start at Central Michigan University, he had 10 tackles and his first career interception. Against Indiana University, he made 14 tackles. Against Georgia State University, he had 14 tackles and one interception. As a junior, he started the first 6 games at middle linebacker, before being lost for the season with an injury. Against North Carolina Central University, he had 39 tackles, one sack, one pass defensed and a forced fumble. Against Bethune-Cookman University, he made 11 tackles and one sack. Against the University of Arizona, he had 10 tackles and a forced fumble. As a senior, he was a part of a defense that ranked No. 1 in the FCS 1-AA. He helped the school earn its 15th MEAC Championship, winning 17-3 against Norfolk State University, where he made 10 tackles, and one sack. He started 13 games, registering 115 tackles, 19 tackles for loss, 7.5 sacks, 5 passes defensed, one interception, one forced fumble and a fumble recovery. Against Alabama A&M University, he had 12 tackles, 3 sacks and one pass defensed. Against Bethune-Cookman University, he made 16 tackles, one sack and a fumble recovery. He also earned Mid-Eastern Athletic ConferenceDefensive Player of the Year and All-conference honors. He finished his college career with 41 games, 271 tackles, 31 tackles for loss, 11.5 sacks, 4 interceptions, 9 passes defensed, 2 forced fumbles and 3 fumble recoveries.
Professional career
Green Bay Packers
Thomas was signed as an undrafted free agent by the Green Bay Packers after the 2014 NFL Draft on May 12. On August 26, 2014, he was placed on the Injured reserve list with a knee injury. Thomas was released after reaching an injury settlement on August 30. On November 3, he was signed to the Packers' practice squad, where he spent the rest of his rookie season. Thomas was signed to a future contract on January 20, 2015. He was waived on September 5.
Thomas was signed to the Dallas Cowboys' practice squad on September 8, 2015.
Green Bay Packers (second stint)
On September 21, 2015, Thomas was signed to the Green Bay Packers' active roster off the Cowboys' practice squad. He appeared in 14 games, making 24 tackles, one sack, one forced fumble, 4 quarterback pressures, 2 passes defensed and 9 special teams tackles. He played in the 2 playoff games and had eight tackles. In 2016, he appeared in 16 games at inside linebacker, making 77 total tackles, 62 solo tackles, 8 passes defensed, one interception and one fumble recovery. He recorded his first NFL interception against Blake Bortles and the Jacksonville Jaguars in Week 1. He collected 10 tackles both against the Seattle Seahawks and Chicago Bears. On December 18, Thomas laid a hit on Chicago'sKa’Deem Carey with so much force, that the "C" decal on Carey's helmet flew off. The Packers won the game 30–27. He played in all 3 playoff games, tying for No. 4 on the team with 13 tackles. Thomas re-signed with the Packers on March 7, 2017. He appeared in 12 games, missing 4 contests with an ankle injury. He finished with 14 tackles, a half sack and one pass defensed.
Dallas Cowboys (second stint)
On March 21, 2018, Thomas signed a two-year deal with the Dallas Cowboys. He was a backup, appearing in 10 games, after suffering a foot injury in the Week 5 game against the Houston Texans and missing next four games. He posted 6 tackles, one quarterback pressure and 5 special teams tackles. In 2019, he appeared in 15 games, registering 36 tackles, one quarterback pressure, one forced fumble and one pass deflection. On March 31, 2020, Thomas re-signed with the Cowboys.
NFL career statistics
Regular season
Postseason
Personal life
Thomas' father, Joe Thomas, Sr., attended his alma mater, South Carolina State University, and became the oldest player to play in a NCAA Division I game on November 19, 2016, when he had a carry for three yards. Unfortunately the father and son were never teammates at South Carolina State since Joe Thomas Sr. was unable to play during Thomas Jr.'s tenure from 2010-2013 after suffering injuries in a car accident.
