He played college football for the Alabama Crimson Tide and was selected in the third round of the 2020 NFL draft by the Patriots.

[1][2] As a senior, Jennings was named first-team 4A All-State and the 4A Lineman of the Year after posting 170 tackles with 88 solo stops, 14 sacks, nine pass breakups and two forced fumbles.

[7] Jennings suffered what was initially diagnosed to be a PCL injury in the final minutes of the 2018 Sugar Bowl against Clemson, causing him to miss the 2018 College Football Playoff National Championship Game.

He finished the year with 51 tackles, including 14 for loss, 6.5 sacks, with an interception, a team-high 11 passes defended and two fumble recoveries (one of which was returned for his first career touchdown).

[14] He made his NFL debut in the season opener on September 13, 2020, against the Miami Dolphins, playing nine snaps on defense in a 21–11 win.