After Lino Červar became head coach of the Croatia men's national handball team in March 2017, Horvat was appointed his assistant. As a member of his coaching staff he participated in European championships in 2018 and 2020, and in World championships in 2019 and 2021. Following the latter tournament where Croatia finished in 15th place, Červar resigned and Horvat was appointed his successor as head coach of the Croatia men's national handball team.