He was the judge in the trial of Joan of Arc and played a key role in her execution.

In 1407, Cauchon was part of a mission from the crown of France to attempt to reconcile the Schism between the rival claimants to the papacy: Boniface IX and Gregory XII.

Upon Cauchon's return, he found Paris in turmoil over the assassination of the Duke of Orléans under orders from John the Fearless.

University theologians sympathized with John and published a justification of the assassination as tyrannicide by arguing that the Duke of Orléans had been planning to usurp the throne.

It is also known that Cauchon had been the dean of the University of Paris, where he had studied, and that, by 1423, he became Henry VI of England's personal counsellor.

The English regent, the Duke of Bedford, was anxious to preserve the claim of his nephew and charge Henry VI of England, grandson of Charles VI and nephew of Charles VII, to the throne of France, as per the Treaty of Troyes.

Cauchon played a leading role in negotiations to gain Joan of Arc from the Burgundians for the English.

Cauchon organized events carefully with a number of ecclesiastics, many of whom came from the pro-English University of Paris.

Concerned for the regularity of the proceeding, Bishop Cauchon forwarded a bill of indictment to Paris in order to obtain the opinion of university clerics, who agreed with the charges.

When constable Arthur de Richemont returned to favour with Charles VII of France in 1436, Cauchon went as ambassador to the Council of Basel.

He was active for the unsuccessful English side in the peace negotiations that ended in reconciliation between the French and the Burgundians.

There is not any marking that indicates the exact location of his burial site, but his skeleton was re-discovered during a renovation of the pavement of the vault in 1931.