A Corsican by birth, he joined the French Royal Army as a volunteer in 1770 and was quickly appointed an officer.

Transferred to the Army of Italy, he assumed command of the 46th Line Infantry Demi-Brigade in February 1794.

When Bonaparte took command of the Army of Italy in the spring of 1796 Fiorella led a brigade in Jean-Mathieu-Philibert Sérurier's division.

During the Battle of Castiglione on 5 August 1796, he took command of Sérurier's division and led it to attack the Austrian left rear.

Despite joining Napoleon for the Hundred Days, he managed to secure retirement with the rank of General of Division commander in 1817.