[2][3][4][5] Having won the national scudetto with both the under-15 and the under-17 in Rome, he made his first appearance in the professional squad under José Mourinho on the 24 October 2021, figuring on the team sheet for a Serie A game against Napoli, along with his Primavera teammate Felix Afena-Gyan.

[3][4][5] Missori made his professional debut for Roma on the 25 November 2021, replacing Henrikh Mkhitaryan for the last 10 minutes of a 4–0 home Conference league win against Zorya Luhansk.

[14][15] On 29 June 2023, Missori joined Serie A club Sassuolo, together with team-mate Cristian Volpato,[16][17] for a cumulative €10 million transfer fee, plus a 15% sell-on clause in favor of Roma for both the players.

[18] He made his debut for the club on 20 August, coming on for as a second-half substitute for Matías Viña in a 2–0 home league defeat to Atalanta.

[23][24] He was included in the under-18 squad that took part in the 2022 Mediterranean Games in Oran, Algeria,[25] with the Azzurrini eventually winning the silver medal after losing 1–0 against France in the final match.