Fitzgerald, Lord Walter (1858–1923), soldier and antiquary, was born 22 January 1858 in Dublin, fourth son of Charles William Fitzgerald, 4th duke of Leinster, and his wife Lady Caroline, third surviving daughter of the 2nd duke of Sutherland. Educated initially in Cheam, Surrey, he then followed family tradition by attending Eton. He entered the Royal Military College at Sandhurst and was gazetted, on being commissioned, to the 4th Battalion of the 60th Rifles. Posted to India he later served with the 8th Battalion of the 60th, before retiring with the rank of captain in 1888. On returning to Ireland he subsequently served as an officer of the Carlow militia (1888–98).
For the remainder of his life Fitzgerald devoted himself to historical and genealogical studies. Dr Peter Harbison describes him in a commemorative article as ‘one of the great neglected giants of Irish antiquarian studies’ (Kildare Arch. Soc. Jn., xv (1973–4), 230–31). Preferring manuscript sources to published works, Fitzgerald engaged in a wide range of studies, researching aspects of folklore, archaeology, and the origin of Irish place names. The genealogy of the Fitzgerald family was also of major interest to him. He was a fellow of the RSAI from 1888, serving on the society's committee on several occasions. A founding member of the Kildare Archaeological Society in 1891, he was its secretary from 1893 till his death. He was also elected MRIA (1890) and in 1904 he became editor of the Journal of the Association for the Preservation of the Memorials of the Dead in Ireland. In this latter capacity he toured the country's western and southern counties, recording medieval tombstone inscriptions, and contributed many illustrated articles to the journal. Indeed, several tombstones that Fitzgerald studied have since been destroyed and his writings remain the only records of such monuments. He was a prolific writer, publishing a great number of articles, both in his own name and under the pseudonym ‘Omurethi’, mostly in the journals of the Kildare Archaeological Society and the Royal Society of Antiquaries of Ireland. Published articles included ‘An account of the arrest of Lord Edward Fitzgerald’ (1899), ‘The principal gentry of the county of Kildare in the year 1600’ (1902), and ‘Discovery of a sepulchral kist near Castledermot’ (1917). He died 31 July 1923 at Kilkea Castle, Mageny, Co. Kildare, and was buried in the family vault at Carton, Maynooth. He never married.
Under the terms of his will Lord Walter Fitzgerald's books, manuscript notes, drawings, and photographs were donated to the RSAI. They remain in the archives of the society's house at 63 Merrion Square, Dublin. There are also some of his papers in the NLI, the RIA, and TCD.