Cybo was born 16 July 1613 in Genoa, the fifth of fourteen children. He was the son of Carlo Cybo Malespina, the son of Alderano Cybo, Duke of Ferentillo, of the family of the Princes of Massa e Carrara. His mother was Brigida Spinola, the daughter of the Marchese di Calice, Giannettino Spinola. He went to Rome in 1641, as prelate and Referendary of the Tribunal of the Two Signatures to Pope Urban VIII. His family had been forced into exile, due to the murder of the mistress of Alderano's brother-in-law, Jacopo Salviati, allegedly at the instigation of his wife, Veronica, Alderano's sister. The family took up residence in the Palazzo Salviati in Rome.
Ecclesiastical career
In 1644 Cybo was appointed papal majordomo. On 6 March 1645, Cybo was elevated to the rank of Cardinal by Pope Innocent X, and named Cardinal-Priest of Santa Pudenziana. In 1646 he was named papal Legate in Urbino, and in 1648 papal Legate in the Romandiola. In 1651 he became Legate in Ferrara. On 24 April 1656 he was appointed Bishop of Jesi. The Cardinal held a diocesan synod in Jesi from 4 to 6 July 1658. He resigned the diocese on 10 December 1671, in favor of his brother Lorenzo Cybo. In 1677, Cardinal Cybo was appointed papal Legate in Avignon. He held the office until 1690, though he administered his office only through appointees, never visiting personally. On 6 February 1679 Cybo was appointed suburbicarian Bishop of Palestrina by Pope Innocent XI. He was transferred to the diocese of Tusculum on 8 January 1680. He was promoted to the diocese of Porto e Santa Rufina on 8 January 1680. He became Dean of the College of Cardinals and Bishop of Ostia e Velletri on 10 November 1687. Cybo participated in the papal conclaves of 1655, 1667, 1669–1670 and 1676. As Dean, he presided over the Papal conclave of 1689 and the conclave of 1691. .
In 1676, Cybo was appointed Cardinal Secretary of State by Pope Innocent XI; he held the post until the death of Pope Innocent in 1689. In 1698, Cardinal Cybo held a diocesan synod at Velletri on 24 and 25 November. The constitutions of the synod were published. Cybo died on 22 July 1700 in Rome, and was buried in the Cybo Chapel of the church of Santa Maria del Popolo, which he had radically rebuilt by Carlo Fontana and Carlo Maratta to glorify the achievements of his family.
