His eldest brother, George, 2nd Earl of Bristol, became Lord Lieutenant of Ireland in 1766 and helped to secure his election as Bishop of Cloyne in 1767. Bishop Hervey displayed great enthusiasm for improving the property of the see of Cloyne which opened the way for his translation to the well endowed bishopric of Derry a year later. As Bishop of Derry, Hervey quickly developed a reputation for being "the most worldly, most eccentric, most talked-about priest in the Church of Ireland".