[2][3] Maccelli began his junior career with HC Turun Palloseura (or TPS) of the Finnish Liiga.

Maccelli signed a three-year entry-level contract with Arizona on April 29, 2020, while still playing for Ilves.

[7] On July 17, 2020, it was announced that Maccelli would stay at Ilves after an open-ended agreement was reached between the Finnish team and Arizona.

[4] For the 2021–22 season, Maccelli returned to North America, joining Arizona's American Hockey League (AHL) affiliate, the Tucson Roadrunners.

He suffered a lower-body injury that led to some missed time, but upon his return, scored seven goals and 23 points in his next 30 games.

[15] He played for the team again during the 2020 World Junior Ice Hockey Championships, scoring two goals and five points in seven games.