Born in Paris to an affluent family, Brienne excelled at his studies, obtaining a doctorate while still in his early 20s. He entered the church and progressed through the ranks, becoming an archbishop in 1763. Politically astute and a very efficient administrator, Brienne served in important bureaucratic roles in the church and became known as a reformer.
In May 1788, Calonne was removed and replaced with Brienne, who attempted to push through a number of reforms not dissimilar to Calonne’s. This led to Brienne’s own sacking from the ministry.
Brienne became a cardinal in late 1788 and moved to Rome. In 1790, he returned to France to swear the oath required by the Civil Constitution of the Clergy, an act that saw him stripped of his cardinalship by the Vatican.
Brienne later renounced Catholicism altogether but was nevertheless arrested during the Reign of Terror, dying in prison.