He began his military career when twelve years old under Facino Cane, a condottiero then in the service of the Marquess of Montferrat and later Gian Galeazzo Visconti, duke of Milan.
[2] On the death of Cane, the duchy was divided among his captains; but Gian Galeazzo's son and heir, Filippo Maria, determined to reconquer it by force of arms.
He was well received in Venice, for the republic was beginning to fear the ambitions of the Visconti, and the new doge, Francesco Foscari, was anxious to join the Florentines and go to war with Milan.
A man of ability, his great mistake was that he failed to see that he could not do with a solvent and strong government what he could with bankrupt tyrants without military resources, and that the astute Visconti meant to ruin him for his abandonment.
An opera Le Comte de Carmagnola with a book by Eugène Scribe and music by Ambroise Thomas was produced at the Paris Opéra on 19 April 1841.
A sculpted porphyry head widely thought to represent Justinian, on the exterior facade of St Mark's Basilica in Venice, has been nicknamed Carmagnola following Bussone's beheading.