Clark appeared in all 13 games as a true freshman at UCLA in 2013.[3] He started four games and had 31 tackles. As a sophomore in 2014, Clark was a second-team All-Pac-12 Conference selection after starting all 13 games and making 58 tackles.[4][5][6] Already established as a strong run defender, he improved as a pass rusher as a junior after entering 2015 with just one career sack. He had a career-high three sacks against Washington State.[7] He was named third-team All-American by the Associated Press and was the lone Bruin named first-team All-Pac-12.[8][9] Clark had a career-high 11 tackles in the Foster Farms Bowl against Nebraska, and ranked second on the team with 75 tackles and six sacks. After the season, he decided to forgo his senior year and enter the 2016 NFL draft.[10]
Clark was selected in the first round (27th overall) by the Green Bay Packers in the 2016 NFL Draft.[14]
On July 17, 2016, the Green Bay Packers signed Clark to a four-year, $9.36 million contract with $7.18 million guaranteed and a signing bonus of $5.00 million.[15][16]
He began his rookie season as a starting defensive tackle alongside veteran Mike Daniels. He was also named a backup and rotational defensive end in the Packers' 3–4 defense.[17]
Clark made his professional debut in the Packers' season opener against the Jacksonville Jaguars and made one assisted tackle in the 27–23 victory. On September 25, 2016, he made his first career start against the Detroit Lions and racked up a total of four tackles in the Packer's win. In Week 14, Clark made four combined tackles during a 38–10 victory against the Seattle Seahawks.[18] As a rookie in 2016, Clark finished with 21 tackles and two passes defended in 16 games.
In Week 13 of the 2017 season, Clark recorded 1.5 sacks, his first of his NFL career and 6 combined tackles in a 26–20 overtime win over the Tampa Bay Buccaneers. He finished the season with 4.5 sacks and 55 tackles.
Clark had a breakout season in 2018, recording 55 tackles, three passes defensed, and six sacks, and was named a Pro Bowl alternate. He suffered an elbow injury in Week 14 and was placed on injured reserve on December 25, 2018.[19]
On April 22, 2019, the Packers picked up the fifth-year option on Clark's contract.[20]
On August 15, 2020, Clark signed a four-year, $70 million contract extension with a $25 million signing bonus.[21]
In the Divisional Round of the playoffs against the Los Angeles Rams, Clark recorded 1.5 sacks on Jared Goff during the 32–18 win.[22] On December 23, 2021, Clark was named to his second Pro Bowl.[23]
On February 23, 2022, Clark agreed to a restructured deal that converted $13.6 million into a signing bonus to save $10.9 million of salary cap space.[24]