Born in Pontremoli, in the province of Massa-Carrara, son of the magistrate and fascist politician Enrico Ferri (MEP, Member of the Chamber of Deputies, Minister of Public Works in the De Mita government and Secretary of the PSDI), he graduated in law from the University of Pisa in 1993.

[2] On July 6, 2014, during the renewal of sixteen members of the High Council of the Judiciary (CSM), a controversy arose regarding an SMS sent by Ferri to his former colleagues from the Magistratura indipendente, in which he directed their votes in favor of Lorenzo Pontecorvo, a section president at the Civil Court of Rome, and Luca Forteleoni, Substitute Prosecutor in Nuoro.

[5] In the 2018 political elections, he ran as a candidate for the Chamber of Deputies in the single-member constituency Tuscany – 08 (Massa) as part of the center-left coalition representing the Democratic Party (PD).

Following the split of the PD by the group of Renziani MPs, Cosimo Ferri joined Italia Viva in September 2019, the party founded by Matteo Renzi with liberal and centrist leanings.

[9][10][11] In the 2022 political elections, he was re-nominated as a candidate for the Chamber of Deputies in the single-member constituency Tuscany – 02 (Massa) for the Action – Italia Viva list.