Like Lamache and Le Taillandier, Jules Devaux hailed from the Normandy region. He was born on July 18, 1811, in the town of Colombieres, Calvados. His father, Marie Adrien Devaux was a country doctor, probably of peasant stock. After attending the College Royal in Caen, Jules came to Paris to study medicine, probably in 1830. It was there that he met Ozanam and his friends. He took part in the Conference of History but did not seem to have been very active in the debates, perhaps because he was studying medicine and not law.
He was one of the seven founders and attended the early meetings of the Society. He took up the collection of funds at the first meeting by walking around with his hat held behind his back. He then became the first treasurer of the Conference and later the first treasurer of the General Council. Jules may have worked with Sr. Rosalie Rendu before the formation of the Society. Regardless, it was he who, at the urging of Emmanuel Bailly, was delegated to approach her so that the newly formed Conference of Charity would be well-mentored in the work of charity.
Leaving Paris in 1839 after submitting his medical thesis, Devaux settled in Trivieres, Normandy. After his mother’s death, he temporarily abandoned medical practice to travel, especially in Germany. He tried to found the first Conference there but did not succeed. He married Louise Alice Pasquet in Paris on April 30, 1848, and they had at least one son, who recorded some of his father’s memories. The remainder of his life is not well-known. He died in Paris on October 27, 1880.