Antoine d'Ursel was born on 23 January 1896 in Brussels, Brussels-Capital, Belgium. He was married to Marguerite de La Barre d'Erquelinnes and Jeanne Thibault. He died on 24 December 1943 in Biriatou, Pyrénées-Atlantiques, France.
Member of an aristocratic Belian family, code-name Jacques Cartier, he was an important part of the Comet line. He drowned in the Bidassoa while trying to cross into Spain.