Guillaume Desjardins or Desgardins, de Gardinis, or Jardinis, doctor of medicine, was born about 1370 at Caudebec in Caux.

He appears in 1403 as priest of the diocese of Rouen, master of arts, and student in medicine.
In 1408 he had first ranking as licentiate in medicine, and the following month was numbered among the master regents of that faculty. From November, 1412, to November, 1413, Desjardins did not teach at Paris, but he took up his courses again at the reopening of the school year in 1414.

On December 6, 1418, the Faculty considered him as a regent, although he was ill in Rouen, which was then besieged, and had not been able to return to his post. Desjardins was never to return to Paris.

He was personat of Mireville in 1415, and was provided by authority of Henry V with the benefice as curé of Saint Laurent de Bacquepits in the diocese of Evreux, which he exchanged for the benefice of Saint Pierre de Neufmarche. He was undoubtedly allied from that time with the English party, for he was named, in succession, to two canonicates in 1421, one at Bayeaux, and the other in the church at Rouen where his brother, Robert Desjardins, died in the early part of August, 1438.

He was a rich man, having at Sahurs a rather important fief, and possessing beautiful books.
Guillaume Desjardins practiced medicine at Rouen and passed for a liberal. He protected at Paris the students of his Nation, contributing towards the acquisition of a building in which they could pursue their studies. He was at Rouen one of the benefactors of the Hôtel Dieu de la Madeleine.

We know that he visited Jeanne in prison, on the orders of the Earl of Warwick, when the English were afraid she would die a natural death. Guillaume Desjardins found that she had a fever; with his colleague and confrère, Guillaume de la Chambre, he prescribed that she be bled.
His opinion at the Trial followed that of the Abbot of Fécamp, Gilles de Duremort.