Walsh was drafted by the New Jersey Devils in the third round (81st overall) of the 2017 NHL Entry Draft. On August 10, 2020, he signed a three-year, entry-level contract with the Devils.[1] Walsh made his NHL debut for the Devils on April 26, 2022, against the Ottawa Senators and recorded his first NHL assist.[2]
In game 2 of the preliminary round of the 2023 Calder Cup playoffs, on his 24th birthday, Walsh scored the game-tying goal against the Laval Rocket with just two seconds left in regulation. Utica went on to win the game in overtime, clinching the series.[3]
After a lone season within the Bruins organization, Walsh left as a free agent to sign a one-year, two-way contract with the Los Angeles Kings on July 1, 2024.[5]