[4] During the 2015–16 season, Pelletier captained the Typhon du SSF-Québec Bantam AAA team[1] while tallying 50 points over 31 games.
[6] During the Blizzard's 2017 playoff run, Pelletier collected 15 goals and 14 assists for 29 points over 17 games as he led the team to the championships.
[7][8] Pelletier also received the Trophée Patrice-Bergeron as the league's most sportsmanlike player[9] and was named to the LHMAAAQ First All-Star Team.
Pelletier scored the game-winning goal over the Regina Pat Canadians to lead the team to the Telus Cup gold-medal game.
[15] While skating alongside Mika Cyr and Jeremy McKenna, Pelletier continued to be a physical and offensive force for the Wildcats.
[27] He was also praised by Troy Dumville of NHL Central Scouting who called him "the smartest player on the board from the Quebec Major Junior Hockey League.
Although he was selected to represent Team Canada at the 2020 World Junior Ice Hockey Championships, a concussion prevented him from playing in the tournament.
[33] When the league concluded the season early due to the COVID-19 pandemic, Pelletier had accumulated 32 goals and 50 assists for 82 points over 57 games.
As he had only accumulated eight minor penalties over that period, he was named the recipient of the Frank J. Selke Memorial Trophy as the most sportsmanlike player in the QMJHL.
[35] On June 5, after three full seasons with the Moncton Wildcats, Pelletier was traded to the Val-d'Or Foreurs in exchange for Mattias Cloutier and draft picks.
[39] Pelletier quickly earned a spot on the Heat's top line with Adam Ružička and Matthew Phillips.
[40] Pelletier consistent offensive output through October and November played an important role in the Heat maintaining a 11–2–2 record through the first 15 games of the season.
[41] He quickly became the third fastest rookie in the 2021–22 season to record 10 goals[42] and was praised by general manager Brad Pascall for his ability to adapt to the professional level.
[43] Once Ružička was called up to the NHL, Pelletier and Phillips gained Glenn Gawdin as their top line centerman.
[47] Due to the Heat's top record in the league, they earned a first-round bye for the 2022 Calder Cup playoffs.
Pelletier made his Calder Cup playoffs debut with the Heat during Game 1 of their Pacific Division best-of-five semifinal series against the Bakersfield Condors.
[57] After serving as a healthy scratch for six games,[58] he made his NHL debut on January 21 against the Tampa Bay Lightning.
As the Flames had failed to qualify for the 2023 Stanley Cup playoffs, Pelletier was returned to the Wranglers for the remainder of their season.
He scored the overtime game-winning goal in Game 1 of the 2023 Calder Cup playoffs to lead the team over the Abbotsford Canucks in the Pacific Division semifinals.
[67] Pelletier scored his second goal of the postseason in Game 1 of the Wrangler's Pacific Division Finals against the Coachella Valley Firebirds.
Pelletier, along with Andrei Kuzmenko, and two draft picks, was traded to the Philadelphia Flyers in exchange for Joel Farabee and Morgan Frost.