In the years to follow his youth football coaches had to keep a copy of his birth certificate on file to dispute claims that he was too old to play.

[4][5] While at the University of Georgia, Smith played college football under head coaches Mark Richt and Kirby Smart.

[25][26] In Week 14 against the Los Angeles Rams, Smith made six tackles and recorded his first career interception off Jared Goff and returned the ball 22 yards to the four-yard line as the Bears won 15–6.

[32] On January 6, 2019, in the Bears' 16–15 loss to the Philadelphia Eagles in a Wild Card playoff game, Smith led the team with seven tackles and made an interception off Nick Foles.

[36] In Week 11 against the Rams on Sunday Night Football, Smith recorded a team high 11 tackles and intercepted a pass thrown by Jared Goff in the 17–7 loss.

[37] In Week 13 against the Lions on Thanksgiving Day, Smith recorded a team high 15 tackles and sacked rookie quarterback David Blough twice in the 24–20 win.

[39] In Week 9 against the Tennessee Titans, Smith recorded a team-high 11 tackles and sacked Ryan Tannehill once during the 24–17 loss.

[40] In Week 10 against the Vikings on Monday Night Football, Smith recorded a team-high 14 tackles and sacked Kirk Cousins once during the 19–13 loss.

However, he was inactive in their appearance, a 21–9 loss against the New Orleans Saints, after suffering an elbow injury in the final game of the season.

[48] On April 27, 2021, the Bears exercised the fifth-year option on Smith's contract,[49] which guarantees a salary of $9.7 million for the 2022 season.

[50] On September 19, Smith intercepted a pass by Joe Burrow and returned it 53 yards for his first defensive touchdown in a 20–17 win against the Cincinnati Bengals.

[58] In early August 2022, Smith announced that while he tried to negotiate a contract extension during the offseason, he has requested the Bears trade him stating the reason being the "new front office regime doesn't value me here.

On August 20, Smith ended his hold out from practices and stated he would no longer continue negotiating with the Bears' front office for the remainder of the 2022 season.