He was the son of Malatesta Guastafamiglia, lord of Pesaro and Rimini. He changed his name to Ungaro when King Louis I of Hungary created him knight in December 1347. He married Costanza, daughter of Obizzo III d'Este, Marquis of Ferrara, in 1363.
After being imprisoned in the war of Louis of Taranto in southern Italy, he fought as Papal commander for cardinal Gil de Albornoz against the Ordelaffi and the Manfredi. On April 16, 1363 he severely defeated Bernabò Visconti and in the following years he often supplanted his old uncle Galeotto I Malatesta as Papal commander-in-chief.
He died in 1372.
- Detailed report of military actions (in Italian)