Francesco Camarda, 15 years and 260 days old, became the youngest player in Serie A history on Saturday.
AC Milan used him as a substitute in their win over Fiorentina.
The previous youngest debutant was Wisdom Amey of Bologna, who was 15 years and 274 days old when he made his debut in 2021.
The Premier League record is held by Ethan Nwaneri, who was 15 years and 181 days old when he played for Arsenal against Brentford in September 2022.
Camarda was called up to the first team with Olivier Giroud suspended and Noah Okafor injured.
He only made his Uefa Youth League debut in September, scoring two goals against Newcastle United.
Camarda is one of only eight players to have made their debut in the Italian top flight before their 16th birthday.
