Born in L'Aquila (AQ) on 11 March 2001, Filoni took his first steps in minibasketball and the youth sector of Nuovo Basket L'Aquilano. Niccolò then continued his career in the youth sector of Oxygen Bassano, a club with which he also made his debut at senior level, in the Venetian Serie C Gold.
In the summer of 2018 he wore the national 3x3 Under 18 tank top while participating in the Youth Olympics in Buenos Aires. On that occasion she won the bronze medal in the slam dunk competition. In 2019 Filoni is captain of the Italy Under 18 team which finishes in ninth place at the European Championships held in Greece. In 2019/20 he played in Rieti, his first adventure in A2, scoring 3.6 points per game on average.
In the last two years, he took the field with Kleb Basket Ferrara (Serie A2), contributing to the playoffs in both seasons. Now he comes to Bertram Derthona to start a new chapter in his career.