Gregory XIV had a longer reign than his predecessor, but still less than a year. He was never easy in the role; he had a tightly-wound disposition, was prone to nervous laughter, and is reported to have said, "God forgive you! What have you done?" when he found out he had been elected Pope.

Among the good works he accomplished in his 11-month reign, he made slight reparations to former Filipino slaves, and set a rule that Catholics must release all their slaves 'upon pain of excommunication.'