He was one of six children of Ernestine Meyer and Zadoc Kahn, the Chief Rabbi of France; his sisters were Hélène, Anne and Berthe; his brothers were Paul and Edmond.
In 1925, he became one of the eight-member editorial board of La Revue juive (The Jewish Review) - a short-lived journal begun by Albert Cohen, the aim of which was to be at the political centre of the perceived contemporary Jewish renaissance; - other members included Albert Einstein, Sigmund Freud, Georg Brandes and Charles Gide.
[10][11] Upon the defeat of France to Nazi forces in 1940, Zadoc-Kahn's son, Bertrand, a cardiologist at the American Hospital of Paris shot himself in despair.
Katharine Graham, owner of The Washington Post, wrote how her father, Eugene Meyer, the American financier and cousin of Zadoc-Kahn who had lived with him for six months, offered to resettle his family to the US as he had with others.
[12][13][14] Annette Benacerraf, Zadoc-Kahn's grand-niece, related to her husband (Nobel laureate, Baruj Benacerraf) how one of his last known addresses in France was in Le Ruel, Haravilliers in Seine-et-Oise, north-west of Paris (now part of the Val d'Oise département) [a] and from here a letter was sent by Zadoc-Kahn to Désirée Damengout, a nursing colleague at the Rothschild Hospital, containing the following: "I beg you to convey my wishes to all my friends on Santerre Street, nurses and doctors.