Isak Hien was born on 13 January 1999 in Kista, Sweden, to Eritrean parents. He came through Djurgårdens IF and went on a series of loans before establishing himself as a senior centre-back. After moves to Hellas Verona in summer 2022 for around €2.9 million, Atalanta signed him for €8.5 million in January 2024.
Hien arrived at Atalanta during the club's most successful period. He was part of the squad that won the UEFA Europa League in 2023–24 — the club's first major European trophy in their history. The 2024–25 season brought 32 Serie A matches, 8 UEFA Champions League appearances, 2 Coppa Italia matches, and the UEFA Super Cup against Real Madrid.
The 2025–26 season has been steady too: 26 Serie A matches with 1 goal, 9 UEFA Champions League appearances, 2 Coppa Italia matches, and a place in the side as Atalanta's senior central defender.
A 191cm two-footed centre-back with elite size, recovery pace and the technical security to play out from the back in Atalanta's possession-based system, Hien has been a Sweden regular for the senior team. He is one of the most experienced Swedish centre-backs heading into the 2026 FIFA World Cup, alongside Victor Lindelöf and Eric Smith.