Born in Naples, Carafa was the younger son in a powerful noble family. He became a soldier and for seventeen years took part in the bloody wars which ravaged Italy, first on the side of the Habsburg imperial armies, afterwards with French troops.
His uncle, Gian Piero Carafa was elected pope, with the name of Paul VI, and made Carlo a cardinal in 1555.
He had a long and dubious career as a mercenary soldier in Italy and Germany. He was exiled from Naples for murder and banditry and was alleged to have perpetrated the massacre of Spanish soldiers as they recuperated in a hospital in Corsica. His tenure as Cardinal Nephew was not a great success as he and Paul IV brought the Papacy to a humiliating defeat against the Spanish that nearly resulted in another Sack of Rome. Carlo’s government was unpopular in Rome and he developed a reputation for avarice, cruelty and licentiousness, as well as for sodomy.
For instance the cardinal Charles de Lorraine asked the French ambassador in Rome to report to the pope scandals concerning his nephews. In his letter he stated that the courtiers had been scandalized by what they had witnessed, “and among the culprits were openly numbered, those who were closest in blood relations to our Holy Father the pope” had engaged in “that sin so loathsome in which there is no longer a distinction between the male and the female sex.”
These rumors cannot be explained away as political slander. Already the poet Joachim du Bellay who was then in Rome, wrote a sonnet mentioning one Ascanio as the beloved of Carlo Carafa. At first the pope refused to believe the numerous and varied accusations, but he was finally convinced of their veracity.
In January 1559, Paul IV finally accepted the accuracy of the accusations made and exiled both his nephews from Rome and replaced Carlo as Cardinal Nephew with Carlo’s own nephew Alfonso Carafa.
With the death of Paul IV, who had already limited a part of his power, he was imprisoned and judged by the new pope, Pius IV , for a lengthy series of crimes ranging from homicide to heresy, which also included sodomy. Carlo was condemned and executed.