The ancestors of Xavier de la Chevalerie are mainly French and Belgian. His father, Christian de la Chevalerie (1895–1966), a Belgian native, once a director of a Champagne-maker Company, married a French girl, Alyette de Beaulaincourt (1890–1976). In 1916, as a wounded of the Belgium Royal military forces, being treated at the hospital of Mortain (Manche), Christian met his wife, a native of Mayenne. Xavier de la Chevalerie is the nephew of Xavier de Beaulaincourt, Benedictine monk, who was a friend of the General de Gaulle at the school of the Immaculate Conception, rue de Vaugirard in Paris.