L'Heureux, 18 (5/15/03), was selected by the Predators in the first round (27th overall) of the 2021 NHL Draft on Friday. Drafted out of the QMJHL's Halifax Mooseheads, the 5-foot-11, 196-pound forward was second among team skaters in points (39), goals (19) and penalty minutes (47) and tied for fourth in assists (20) in 2020-21, his second full QMJHL season. He recorded at least two points in 10 of his 33 games, highlighted by multiple four-point efforts, including a two-goal, two-assist performance on April 2 vs. Cape Breton; he also tallied a four-game goal streak (4g) and five-game assist streak (8a), both career bests. L'Heureux posted 20 goals and 53 points in as a rookie in 2019-20 with the Moncton Wildcats, the team that selected him third overall in the 2019 QMJHL Entry Draft.
In addition to skating for Canada at the 2019 World U-17 Hockey Challenge, the Montreal, Que., represented his province at the 2019 Canada Winter Games and scored the game-winning goal in overtime of the championship game vs. Ontario.