When he was around the age of five the family moved to Fort Myers, Florida, where he met future Columbus Blue Jackets draft pick Gavin Brindley, who became a close friend and with whom he would play youth, junior, and collegiate ice hockey.

[7] Making good on his commitment to Michigan, Casey joined fellow Devils draftees Luke Hughes and Ethan Edwards on the Wolverines for the 2022–23 season.

[7] Michigan won the Big Ten Conference, but lost in the semifinals of the 2023 Frozen Four to the eventual champions, Quinnipiac University.

[14][15] In his lone under-18 tournament appearance, Casey represented the United States at the 2022 IIHF World U18 Championships, scoring six points in as many games.

[17] The following year, however, at the 2024 World Junior Ice Hockey Championships, he would be rostered,[18] and would record six assists in six games en route to a gold medal.