His father, Jean d'Estouteville, Sieur de Vallemont and Grand Chamberlain of France, had fought at Agincourt, was captured, and spent twenty years as a prisoner of war.

The family lost a great deal of property and income as a result of the English occupation of Normandy after the Battle of Agincourt.

[11] Chacon also states that d'Estouteville was Doctor Decretorum (Doctor of Canon Law), but various papal documents of Pope Eugenius IV, in particular one of 1435, call him a Papal Notary, a relative of the Kings of France, a Master of Arts, and of Canon Law, as a result of having passed rigorous examinations.

[14] Guillaume D'Estouteville, who was ambitious for the post, immediately rushed to Rome and obtained bulls from Pope Eugene IV on 20 February[15] naming him to the bishopric.

[16] Pope Eugene escaped from the danger by giving d'Estouteville the bishopric of Digne in the Alpes-de-Haute-Provence, a suffragan of Embrun.

[19] A few months after the affair of Angers, Guillaume d'Estouteville was named a cardinal priest in the consistory of 18 December 1439 by Pope Eugene IV,[20] and assigned the titular church of San Martino ai Monti.

Pope Eugene probably derived a bit of satisfaction at granting a red hat to a member of the French royalty without the request or consent of the King.

In March 1451 Pope Nicholas V granted a new set of Statutes to the Canons of the Basilica, which emphasized the decisive power that the Archpriest had over the physical structure of the church and its property.

[27] In April 1453 he was released from his obligation as Bishop of Maurienne and appointed Archbishop of Rouen by Nicholas V.[28] The Canons of Rouen protested the violation of their rights, and Pope Nicholas granted them an Indult on 16 November promising them that, on the death of Guillaume d'Estouteville, they could elect whomever they wished.

[31] At the behest of the Inquisitor General Jean Brehal, Estouteville undertook an ex officio revision of the trial of Joan of Arc.

[32] He then presided over the Assembly of the French clergy which met at Bourges in July and August 1452 to discuss the implementation of the Pragmatic Sanction.

[35] His official mission was to attempt to persuade Charles VII to join in yet another crusade, the one that Nicholas V had tried to launch on 30 September 1453, following the Fall of Constantinople.

He was able to command six votes out of the nineteen participants, but he was defeated by Cardinal Aeneas Sylvius Piccolomini of Siena, who chose the name Pope Pius II.

[42] In 1458 Cardinal d'Estouteville was asked by the Teutonic Knights to be their Protector at the Roman Curia, an honor and office which he accepted.

In January 1459 he accompanied Pope Pius II in his journey to Mantua to meet with the princes of Europe to arrange for a crusade against the Ottoman Turks.

[46] He took part in the Conclave of 27/28–30 August 1464,[47] in which Pope Paul II (Pietro Barbo of Venice) was elected in the first Scrutiny.

[49] Pope Paul died on 26 July 1471, and Cardinal d'Estouteville immediately began campaigning openly for the papacy.

On 15 May 1472 he gave a luncheon there in honor of Cardinal Rodrigo de Borja, who was leaving Rome on a mission to Catalonia and Spain.

D'Estouteville held the position until his death; he was the last non-Italian cardinal to hold the office for nearly five hundred years, until Jean-Marie Villot in 1970.

In his capacity as Bishop of Ostia d'Estouteville had the walls of the town restored, and built the Cathedral of Saint Aurea.

[59] He then had the remains of Saint Monica, the mother of St. Augustine, brought from Ostia Antica for entombment in a marble sarcophagus he had built for them.

[68] Cardinal d'Estouteville performed a number of episcopal consecrations in Rome as part of his duties in the Roman Curia.