Prior to his short papacy, he had been a canon lawyer, diplomat, and chief administrator during the reign of Pope Gregory XIV (r. 1590–1591).

As papal legate to Venice, he helped negotiate the formation of the Holy League, an alliance of Spanish and Italian maritime powers to challenge the Ottoman Empire’s control of the eastern Mediterranean, and which resulted in victory at the Battle of Lepanto.

[citation needed] The surname of his family seems to have actually been Nocetti (or de Nuce), but in fact the future pontiff was called Facchinetti after the humble job carried out by his father, who was a porter.

[citation needed] Giovanni studied at the University of Bologna - which was pre-eminent in jurisprudence — where he obtained a doctorate in both civil and canon law in 1544.

[5] Relinquishing his see to pursue his career in Rome in 1575 and also because of health reasons, he was named the Titular Latin Patriarch of Jerusalem in 1572.

Pope Gregory XIII made him a cardinal on 12 December 1583 as the Cardinal-Priest of Santi Quattro Coronati and he was to receive the red hat and title on 9 January 1584.

This time the Spanish party in the College of Cardinals did not go so far, but they still controlled a majority, and after a quick conclave they raised Facchinetti to the papal chair as Pope Innocent IX.

Mindful of the origin of his success, Innocent IX supported, during his two months' pontificate, the cause of Philip II and the Catholic League against Henry IV of France (r. 1589–1610) in the French Wars of Religion (1562–1598), where a Papal army was in the field.