Farrell played in the first five games of his freshman season and recorded five tackles with one quarterback hurry before suffering an injury.[5] Farrell played in all 15 of LSU's games with three starts as a sophomore and had 46 tackles, seven tackles for loss, and three sacks as the Tigers won the 2020 College Football Playoff National Championship.[6]
Farrell initially announced that he would opt-out of his senior season due to family health concerns regarding the COVID-19 pandemic, but later reversed his decision.[7] Farrell finished the season with 25 tackles, 2.5 tackles for loss, 1.0 sacks, and 1 forced fumble.[8] After considering entering the 2021 NFL draft, he decided to utilize the extra year of eligibility granted to college athletes who played in the 2020 season due to the coronavirus pandemic and return to LSU for a fifth season.[9] Farrell finished the 2021 season with 45 tackles, 9.5 tackles for loss, and two sacks.[10] After the conclusion of his college career, he played in the 2022 Senior Bowl and was named the best defensive lineman for the American Team.[11]
Farrell was drafted by the Las Vegas Raiders in the fourth round, 126th overall, of the 2022 NFL draft.[14] He was placed on the non-football injury list on July 26, 2023.[15]
Farrell was waived by the Chiefs on August 27, 2024, and re-signed to the practice squad, but released two days later.[19][20]
Miami Dolphins
On September 26, 2024, Farrell signed with the Miami Dolphins practice squad.[21] He was promoted to the active roster on November 11. He signed a reserve/future contract on January 7, 2025.[22]