Jacopo Caldora was born in Castel del Giudice (Abruzzo in present-day Molise, then part of the Kingdom of Naples), into a feudatory family.

He began his military career under Braccio da Montone, and, returned to his lands, expanded them by hiring mercenaries from the surrounding mountains.

He was the Feudal Lord of Anversa, Arce, Bari, Campo di Giove, Monteodorisio, Pacentro, Palena, Trivento, Valva and Vasto.

When the Aragonese troops were left under siege in Naples, he changed sides again, winning the title of gran connestabile from Queen Joan, and serving as assistant to the Kingdom's commander-in-chief Muzio Attendolo Sforza.

When his protector Sergianni Caracciolo died, and the marriage of his daughter Maria to Francesco Sforza was annulled by Pope Martin V, he returned to his lands.