His main role on the pitch is Defender. His stronger foot is Right. His estimated market valuation currently stands at 300K €.

His latest transfer saw him join AC Milan U20 from Ascoli via Free on 2025-08-13. The move was reported at 0.5M €.

Across the Italian Campionato Primavera 1 2025-2026, Mattia Piermarini appeared in 3 matches and averaged 0 tackles, 0 interceptions, 0 clearances, and 0 blocked shots per game.