John de Barth Walbach was born on October 3, 1766, in Munster, Haut-Rhin, Alsace, France, and was the third son of French nobleman Count Jean Joseph de Barth and Marie Therese de Rohmer.
Rohan's Hussars, with Walbach as 3rd officer, were sent in 1795 to the French colony of Saint-Domingue (now Haiti) by England to defend British and royalist French planters against the slave revolt and to take the colony from France.