His pontificate was overshadowed by the constant pressure to suppress the Society of Jesus but despite this, he championed their order and also proved to be their greatest defender at that time.

He was also one of the few early popes who favoured dialogue with Protestants and to this effect hoped to mend the schism with the Catholic Church that existed in England and the Low Countries.

[3] Rezzonico was chosen as Bishop of Padua in 1743 and he received episcopal consecration in Rome by Pope Benedict XIV himself,[3] in the presence of Giuseppe Accoramboni and Cardinal Antonio Saverio Gentili as co-consecrators.

[6] Pope Benedict XIV died of gout in 1758 and the College of Cardinals gathered at the papal conclave in order to elect a successor.

Notwithstanding the meekness and affability of his upright and moderate character, he was modest to a fault (he had the classical sculptures in the Vatican provided with mass-produced fig leaves)[8] and generous with his extensive private fortune.

[8] Clement XIII's pontificate was repeatedly disturbed by disputes respecting the pressures to suppress the Jesuits coming from the progressive Enlightenment circles of the philosophes in France.

In France, the Parlement of Paris, with its strong upper bourgeois background and Jansenist sympathies, began its campaign to expel the Jesuits from France in the spring of 1761, and the published excerpts from Jesuit writings, the Extrait des assertions, provided anti-Jesuit ammunition (though, arguably, many of the statements the Extrait contained were made to look worse than they were through judicious omission of context).

The Bourbon kings espoused their relative's quarrel, seized Avignon, Benevento and Pontecorvo, and united in a peremptory demand for the total suppression of the Jesuits (January 1769).

[3] Driven to extremes, Clement XIII consented to call a consistory to consider the step, but on the very eve of the day set for its meeting he died, not without suspicion of poison, of which, however, there appears to be no conclusive evidence.

In support of this policy, he recognised the Hanoverians as Kings of Great Britain despite the long-term residence in Rome of the Catholic House of Stuart.

The pope approved the cultus for several individuals: Andrew of Montereale and Vincent Kadlubek on 18 February 1764, Angelus Agostini Mazzinghi on 7 March 1761, Anthony Neyrot on 22 February 1767, Agostino Novello in 1759, Elizabeth of Reute on 19 July 1766, James Bertoni in 1766, Francesco Marinoni on 5 December 1764, Mattia de Nazarei on 27 July 1765, Sebastian Maggi on 15 April 1760 and Angela Merici on 30 April 1768.

He was described in the Annual Register for 1758 as "the honestest man in the world; a most exemplary ecclesiastic; of the purest morals; devout, steady, learned, diligent..."[12]