Joseph van Cleef was a son of Simon van Cleef and Judith Polak. He married 9 April 1941 in Amsterdam to Esther Agsteribbe, a daughter of Gerrit Agsteribbe and Marianne Bromet.
His siblings, who have been killed also during the Holocaust were Abraham, Mozes, Doortje and Rebecca.
Stadsarchief Amsterdam, archiefkaart Joseph van Cleef