During his time at Genoa, Romero continued to excel and established himself as one of the most promising young defenders in Serie A. His performances attracted the attention of other clubs, and in 2020, he signed for Atalanta on loan with an option to buy. Romero’s time at Atalanta only further enhanced his reputation, as he helped the team secure a top-four finish in Serie A and reach the quarter-finals of the UEFA Champions League.