[1] Tranquill was a four-star recruit coming out of high school, and received offers from several major programs, mostly in the Big Ten Conference.

[1] He played in three games as a sophomore in 2015, with one start, but was lost for the season due to a torn ACL suffered while celebrating after breaking up a pass against Georgia Tech on September 19.

Head coach Anthony Lynn named Tranquill the third middle linebacker to begin the regular season, behind Denzel Perryman and Nick Dzubnar.

On November 7, 2019, Tranquill earned his first career start, replacing Denzel Perryman who was inactive due to an ankle injury, and recorded a season-high 14 combined tackles during a 25–23 loss at the Oakland Raiders.

Tranquill competed against Kyzir White during training camp to be the starting weakside linebacker after the role was left vacant after the departure of Thomas Davis Sr.

Defensive coordinator Gus Bradley named Tranquill the backup weakside linebacker behind White to begin the regular season.

During training camp, Tranquill competed against Kyzir White, Kenneth Murray, and Kyler Fackrell to be one of the starting inside linebackers after long-time veteran Denzel Perryman left via free agency.

[21] Head coach Brandon Staley named Tranquill a backup inside linebacker to begin the season, behind Kenneth Murray, Kyzir White, and Kyler Fackrell.

Tranquill entered training camp slated to be a starting inside linebacker after Kyzir White departed in free agency and Kenneth Murray sustained an ankle injury the previous season.

[26] In Week 6, he collected eight combined tackles (six solo) and had a career-high two sacks on quarterback Russell Wilson in a 19–16 victory over the Denver Broncos.

[32][33] On September 7, 2023, Tranquill made his regular season debut as a member of the Kansas City Chiefs, making two combined tackles (one solo) in a 21–20 loss to the Detroit Lions.

Tranquill recorded eight combined tackles (four solo) and made half a sack on Justin Fields during a 41–10 win over the Chicago Bears.

On January 28, 2024, Tranquill earned his first start of the 2023 postseason and recorded eight solo tackles as the Chiefs defeated the Baltimore Ravens 17-10 in the AFC Championship.

[36] On February 11, 2024, Tranquill appeared in Super Bowl LVIII, recording two total tackles as the Chiefs defeated the San Francisco 49ers 25–22.