[8][9] On January 8, 2024, Gauthier's NHL rights were traded to the Anaheim Ducks in exchange for Jamie Drysdale and a 2025 second-round draft pick.

"[15] At the conclusion of his sophomore season, having led the NCAA with 38 goals and tying the Eagles' record for most goals in a single season in program history, Gauthier ended his collegiate career in signing a three-year, entry-level contract with the Anaheim Ducks on April 14, 2024.

[16] Gauthier recorded his first NHL goal on November 15, 2024, beating Alex Lyon of the Detroit Red Wings, boosting his team in a 6-4 victory.

[18] He was then selected to represent the United States at the 2022 IIHF World U18 Championships, where he recorded three goals and six assists in six games and earned a silver medal.

[21] He led the team in scoring, recording two goals and ten assists in seven games, tying Czech player Jiří Kulich for top scorer in the tournament.