Immigrated to France as a young man; served in Walsh’s regiment of the Irish brigade and as an aide-de-camp to Louis XV. Served in French expeditionary force in Revolutionary War. Officer of marines on the Bonhomme Richard (1778). Royalist; left France on dissolution of Irish brigade (1791) but later returned and served as maréchal-de-camp to Louis XVIII.
Son of John and Margaret (Barry) Stack of Kelad, County Kerry, Ireland.