ADO Den Haag On 10 August 2025, he made his professional debut with
ADO Den Haag in a 5–1
Eerste Divisie win against
Willem II as a substitute.
AC Milan On 21 August 2025, Italian
Serie A club
AC Milan announced the signing of Balentien from ADO Den Haag, with the intention to involve him in the
Milan Futuro reserve team, set to play in the
Serie D for the
2025–26 season. He signed a contract with the club until 2030. Soon after, he made his debut with Milan Futuro, playing 25 minutes in a
Coppa Italia Serie D game against Trevigliese. Being immediately noticed by first team head coach
Massimiliano Allegri, he was instead promoted to the senior team and called up for the next
Serie A league game against
Lecce, during which he made his debut as a substitute for
Santiago Giménez on the 88th minute. ==International career==