He played college football for the Notre Dame Fighting Irish and was selected by the Jacksonville Jaguars in the fourth round of the 2016 NFL draft.

Day has also played for the San Francisco 49ers, Indianapolis Colts, Cleveland Browns, and Minnesota Vikings.

Considered a four-star recruit by Rivals.com, he was rated as the 18th best defensive tackle prospect of his class.

[1] On August 4, 2011, he committed to play college football at the University of Notre Dame.

[2] Sources: As a true freshman at Notre Dame in 2012, Day appeared in all 13 games and had 23 tackles and two sacks.

[8] Day was selected by the Jacksonville Jaguars in the fourth round (103rd overall) of the 2016 NFL draft.

[15] Day reached Super Bowl LIV with the 49ers, but lost 31–20 to the Kansas City Chiefs.

[17] Day was designated to return from injured reserve on September 30, and began practicing with the team again.