[5] St-Juste attended various college football camps in the United States in the mid-2010s, and was offered a scholarship to play for the Michigan Wolverines under Jim Harbaugh.

[15] He made his NFL debut in the opening game against the Los Angeles Chargers, where he recorded four tackles, but also allowed six catches in a 20–16 loss.

[19] With 35 seconds remaining in Thursday Night Football and the Chicago Bears on fourth and goal, St-Juste made a key stop pushing wide receiver Darnell Mooney, who caught the pass, out of the endzone before Mooney's feet landed on the field and sealed the Commanders' 12-7 victory.

[20] In Week 9 against the Minnesota Vikings, he deflected a touchdown pass attempt from Kirk Cousins which cornerback Danny Johnson intercepted.

[21] The following week's victory over the then undefeated Philadelphia Eagles, St-Juste forced wide receiver Quez Watkins, after catching a 50-yard pass, to fumble the ball allowing safety Darrick Forrest to recover it.