During the summer going into his senior season Gainwell committed to play college football at Memphis over offers from Ole Miss and Tulane.

[5] Gainwell moved to running back during summer training camp and played in four games as a true freshman before deciding to redshirt the rest of the season.

[6] As a redshirt freshman, Gainwell was named the Tigers' starting running back following the departure of Tony Pollard.

[17] Gainwell was happy to be drafted by Philadelphia, as he grew up an Eagles fan, and his favorite player while growing up, Darren Sproles, works for the team as a consultant.

[20] Gainwell appeared in 16 games as a rookie, as he was a healthy scratch for the Eagles' week 11 showdown with the New Orleans Saints.

[23] This performance made him just the sixth Eagles player to rush for at least 100 yards in a postseason game.

[24] Gainwell helped the Eagles reach Super Bowl LVII where they lost 38–35 to the Kansas City Chiefs.