de Brézé had made his name in the English wars when in 1433 he joined with Yolande, queen of Sicily, the constableRichmond and others, in chasing from power Charles VII's ministerLa Trémoille. He was knighted by Charles of Anjou in 1434, and presently entered the royal council. In 1437 he became seneschal of Anjou, and in 1440 of Poitou. During the Praguerie he rendered great service to the royal cause against the dauphinLouis and the revolted nobles, a service which was remembered against him after Louis's accession to the throne. de Brézé fought against the English in Normandy in 1440–1441, and in Guienne in 1442. He was granted the defunct title of comte d'Évreux in 1441 for his role in the strategic maneuvers during the siege of Pontoise led by Charles VII that finally defeated the English in the Ile de France. In the next year he became chamberlain to Charles VII, and gained the chief power in the state through the influence of Agnès Sorel, superseding his early allies Richmond and Charles of Anjou. The six years of his ascendancy were the most prosperous period of the reign of Charles VII. His most dangerous opponent was the dauphin Louis, who in 1448 brought against him accusations which led to a formal trial resulting in a complete exoneration of Brézé and his restoration to favour. He fought in Normandy in 1450–1451, and became seneschal of the province after the death of Agnes Sorel and the consequent decline of his influence at court. He made an ineffective descent on the English coast at Sandwich in 1457, and was preparing an expedition in favour of Margaret of Anjou when the accession of Louis XI brought him disgrace and a short imprisonment. In 1462, however, his son Jacques married Louis's half-sister, Charlotte de Valois, daughter of AgnèsSorel. In 1462 he accompanied Margaret to Scotland with a force of 2000 men, and after the Battle of Hexham he brought her back to Flanders. On his return he was reconciled with Louis XI and reappointed seneschal of Normandy. He inherited the Château du Bec-Crespin from his brother-in-law, Antoine Crespin, in 1454.
de Brézé died in the Battle of Montlhéry on 16 July 1465. He was succeeded as seneschal of Normandy by his eldest son Jacques, Count of Maulevrier. The best contemporary account of Pierre de Brézé is given in the Chroniques of the Burgundian chronicler, Georges Chastellain, who had been his secretary. Chastellain addressed a Déprécation to Louis XI on his behalf at the time of his disgrace.
