McNeill, Hugh Hyacinth (‘Hugo’) (1900–63), soldier, was born 16 April 1900 at Aberdelghy, Howth, Co. Dublin, son of Hugh McNeill, lecturer in classics at UCD, and Abigail (‘Mary’) McNeill (née Murphy). Eoin MacNeill (qv), politician and academic, was his uncle. Of his brothers Olaf and Dermot, the former also followed a military career. Hugo was educated at Holy Faith school, Haddington Road, and at St Enda's, Rathfarnham, Dublin, under Patrick Pearse (qv). McNeill was a member of the Fianna Éireann scouts (1913–17) before serving in the Dublin Brigade, Irish Volunteers (subsequently IRA) in 1917–21. After the Anglo–Irish treaty (December 1921) he joined the National (later Free State) Army as a lieutenant in February 1922, advancing rapidly to colonel-commandant in the same year. He operated mainly in the Dublin area during the civil war (1922–3), making a rare use of aircraft against anti-treaty forces in Dundalk in July 1922. In 1923 he was promoted colonel and assigned to the training staffs of GHQ and the Curragh. He was also adjutant of Dublin Command.
After the army crisis of March 1924, in which he raided the Dublin HQ of dissident officers led by Maj.-gen. Liam Tobin (qv), he became adjutant-general when the suspended general staff was replaced in June. Promoted to major-general in October 1924, he held that rank for the remainder of his career. In October 1925 he became assistant chief of staff and in 1926 was chosen with Col. (later Maj.-gen.) Michael J. Costello (qv) to lead a military mission to the US to study methods of organisation and training at West Point, Fort Leavenworth, and other centres. After his return in October 1927, McNeill was appointed director of a new Temporary (Defence) Plans Division, with a staff including Costello and the other mission members. In October 1928, with government approval for most of his recommendations, he was appointed GOC Curragh Command, the main military training centre. In 1930 he became commandant of the new military college there.
As a man of academic background and disposition, he hoped to educate the public on military matters through the revived army journal, An t-Óglách, edited by Costello. However, McNeill's failure to curb the disgruntled tone of contributors, who openly criticised the Department of Defence and conditions of military service, frightened the government into suppressing the journal's parent body, the National Defence Association, an officers’ forum of which McNeill was chairman. He left the military college in July 1932 to become assistant chief of staff again, returning there in 1937.
In 1940, as the wartime state of ‘Emergency’ mobilised the country to defend its neutrality, he briefly took charge of G.1 training branch of general staff, and became assistant chief of staff for a third time. McNeill's personal approaches to the German legation during the winter of 1940, for assistance in the event of a British invasion from Northern Ireland, made his position on neutrality ambiguous to say the least, but incurred no official consequences. In June 1941 he became GOC 2nd (Spearhead) Division, a command comprising three brigades based in Dublin and later in Maynooth. He commanded them as the invading ‘Redland’ forces in the legendary Blackwater manoeuvres at Fermoy, Co. Cork (September 1942), against the local ‘Blueland’ forces (1st Division based in Cork, commanded by Maj.-gen. Costello). McNeill was romantic and demonstrative by nature; his spectacular military pageants at Dublin's Theatre Royal, and later at the RDS, brought a rousing and satisfying public response.
After the Emergency, in July 1946 McNeill became GOC Eastern Command and retired in October 1951. He married (date unknown) Margaret McKenna; they had three sons, Hugh Patrick, Dermot, and Gearóid. His interests, like his pageants, were flamboyant: sailing, horse-riding, and hunting. He was also a Gaelic enthusiast in the family tradition, signing himself ‘Aodh Mac Neill’, and deeply involved in the Military History Society of Ireland, which he co-founded (1949) and of which he was vice-president. In 1952–4 he was Bord Fáilte organiser of An Tóstal, the Irish national festival, and in 1953 was president of the Organisation of National Ex-servicemen (ONE). Charismatic among soldiers and civilians alike, he had a certain iconic quality. He lived at several addresses, mainly in Dublin; his last was Littleholme, Delgany, Co. Wicklow. He died 17 April 1963 of respiratory failure at St Michael's hospital, Dún Laoghaire, Co. Dublin, and was buried with full military honours at Dean's Grange cemetery.