, Gvardiol was struggling to get into the youth team at Dinamo Zagreb and considered quitting to go and sell fish at the Dolac market in the Croatian capital with his father. However, he decided to continue his career after a family friend drew up a mental map for him titled 'success', with the words 'discipline', 'top club' and 'hard work' highlighted on it.
Gvardiol showed plenty of potential when he was coming through Dinamo's academy. Dalibor Poldrugac, an academy coach for the Croatian giants, said in 2019: "If he's not a starter for Croatia by the time he's 20, somebody should go to jail for it." Gvardiol made his debut for the national team aged 19 in 2021 at the rescheduled European Championship.