After beginning his professional career with Dinamo Zagreb at the age of 16, highly rated Croatian midfielder Alen Halilovic earned a permanent move to Barcelona, where he spent two years before joining Hamburg for a further two seasons.
During his time at the Nou Camp, he played primarily for Barcelona B before spending the 2015–16 season on loan at Sporting Gijon.
After joining Hamburg in 2016, he was loaned out to La Liga side Las Palmas during the 2017–18 campaign.
In 2018, shortly after his 22nd birthday, he signed for AC Milan, the sixth club of his career – while Italy became the fourth different country in which he had played.
The midfielder later had spells with Birmingham City and Reading. He now plays for Fortuna Sittard in the Netherlands.