As of 1535, Sampiero's career was tied to the French House of Valois. He fought successfully for King Francis I, alongside the Chevalier de Bayard, in the Italian Wars; in 1547, he acquired the rank of colonel of the mercenary Corsican troops, and, in accordance with usage, became known by his moniker (indicative of his place of origin). The renown ensured his large fortune, and he married the noblewoman Vannina d'Ornano (he was 49, she was just 15).