Jackson played at George County High School where he was an Army All-American and named Mississippi’s Mr. Football 6A. He was a 4-star recruit according to all three national recruiting outlets and the No. 1 player out of the state of Mississippi.
In 2020 as a freshman, McKinnley Jackson played in 10 games, making 1 start. He earned SEC All-Freshman team honors after compiling 13 tackles and 1.5 sacks. During his sophomore season, he played in 10 games, starting 4 and tallied 14 tackles and a sack.
In 2022, Jackson was named a team captain and played in 8 games, including 7 starts and finished 2nd on the team with 7.0 tackles for loss. In 2023, Jackson has 27 tackles and 3 sacks in 12 games for the Aggies.