Son of Horacio Pacca, marquess of Matrice, and of Cristina Malaspina d'Olivola, Bartolomeo Pacca was educated by the Jesuits in Naples. He eventually joined Clementino School in Rome, before getting into the Ecclesiastic Academy of Rome in 1778. He was close to Pius VI, who made him his secret chamberlain on May 31st, 1785, before appointing him archbishop of  Damietta and apostolic nuncio in Cologne. Bartolomeo stayed in Germany until 1794, then he officiated as apostolic nuncio by the court of Portugal from 1795 to 1802. Close to Prince Dom Joăo and the royal family, he preserved the influence of the Church in this country when all Europe was troubled by the French Revolution and the war.

Pius VII eventually appointed him cardinal and Bartolomeo went back to Rome, from where he strived for the protection of the belongings and the rights of the Church in France. On the orders of Napoleon, he was abducted in Rome with Pius VII in 1809. Transferred together to Grenoble, the two men were eventually separated and put in jail. Bartolomeo was imprisoned in Piedmont, at Fenestrelle Fortress, the largest in Europe (1 300 000m˛) where he remained prisoner for three years and a half.

In 1813, Pius VII, while negotiating a concordat with Napoleon, put pressure so that the Cardinal be freed and the two men met again at Fontainebleau in February. Together, they went back to Rome the following year and Bartolomeo was appointed pro-secretary of State and Finance Minister of the pontifical State. He had Tite triumphal arch refurbished at that time.

Up to the end of his life, he fulfilled important tasks: pro-datary of His Holiness, eventually bishop of Ostia and finally archpriest of Saint John Lateran, he was also a close collaborator to Popes Leo XII, Pius VIII and Gregory XVI. This clergyman had a great impact on his times and the history of the Church as an ardent fighter for the rights of the Church in a troubled period. His last speech, performed in 1843 at the Rome Academy of Catholic Religion and dealing with the current state and the future destiny of the Catholic Church, had a particularly strong impact.

He died in Rome a few months later, in 1844.

His works:

Memorie storiche della nunziatura di Colonia Dei grandi meriti verso la Chiesa Cattolica del clero dell' Universita e de' Magistrati di Colonia nel secolo XVI
Memorie storiche del ministero de' due viaggi in Francia e della prigionia nel Forte di San Carlo in Fenestrelles.
Notizie sul Portogallo e sulla nunziatura di Lisbona
Memorie storiche per servire alla storia ecclesiastica del secolo XIX (1809-1814)
Notizie storiche intorno alla vita e gli scritti di Mons. Franc. Pacca, arcivescovo di Benevento (1752-1775).
Cardinal Pacca's Historical Memoirs on ecclesiastical matters in Germany and Portugal during his nunciature.