Sergej Levak is a Croatian central midfielder from Osijek. After starting locally and developing in Osijek's system, he joined Roma's youth academy in 2023 and trained with the first team while becoming one of the Primavera side's notable midfielders. In July 2025 he moved to Atalanta and was assigned to Atalanta U23 in Serie C. He has represented Croatia at several youth levels from under-15 to under-19.