 O'Donnell married Mariana de Anethan y Mareshal, of Luxemburg.Three of their sons became Spanish generals during the Peninsular War, also known as the Spanish War of Independence.The most famous was Henry O'Donnell, 1st Count of la Bisbal (1769–1834) who was defeated at Vic by Joseph Souham, beaten badly at Margalef by forces under Louis Gabriel Suchet, won a splendid victory at the La Bisbal in 1810 over François Xavier de Schwarz, and successfully concluded the Siege of Pamplona in 1813.