Corcoran, Michael (1827–63), brigadier-general in the American civil war and Fenian, was born in Carrowkeel, Co. Sligo, on 21 September 1827, son of Thomas Corcoran (d. 1845), a retired British army officer who had served in India, and Mary Corcoran (née McDonagh). In 1846 he joined the Irish Constabulary and was stationed at Creeslough, Co. Donegal, but resigned in 1848 after becoming a Ribbonman. In 1849 he emigrated to New York, where he worked as a clerk in the post office and in the office of the city register, and as general factotum for John Heaney who owned the Hibernian Hall at 42 Prince St. This was a central meeting place for the New York Irish; it was used as a dance hall and (from c.1852) as a drill hall for the Irish Fusiliers, 69th Regiment, New York State Militia. This regiment was formed in October 1851, when Corcoran joined as a private. Within six months he was made captain of the company (29 May 1852) and so distinguished himself at the quarantine riots on Staten Island in 1858 that he was made colonel (26 August 1859). By this time he was a member of the Fourteenth Ward general committee and a well known figure in Tammany Hall, who could deliver the Irish vote. After Heaney's death (1854) he took over the running of the Hibernian Hall and married either the widow Heaney, or her niece (sources diverge). In 1858 the hall became a meeting place for the Ancient Order of Hibernians. Corcoran introduced John O'Mahony (qv) to the order in 1859 and then joined O'Mahony's newly founded Fenian Brotherhood.
Corcoran's career suffered a temporary setback (1860) when as colonel of the 69th he refused to parade his regiment for the visit of the prince of Wales to New York, citing political reasons. This made him a hero to Irish communities across America but he was due to appear before a court martial for insubordination when (15 April 1861) President Abraham Lincoln made his first call for troops to defend the union, and the court martial was cancelled. Five days later Corcoran mustered his regiment, which left New York on 23 April. It gave three months service, culminating at the battle of Bull Run, Virginia (21 July 1861), where nearly 200 of its men were killed, wounded, or captured. Corcoran was himself captured and confined at Richmond, Charleston, Columbia, and Salisbury, and was used as a hostage guaranteeing good treatment of confederate prisoners before being released as part of an exchange programme on 15 August 1862. Some months later his first wife died and he married John Heaney's eldest granddaughter. Returning to New York as a union hero, he was appointed brigadier-general of the United States Volunteers and authorised to organise a new brigade, which became known as Corcoran's Irish Legion (to distinguish it from Meagher's Irish Legion). It was assembled over the next few months and consisted of six New York regiments. Many Fenians enlisted; Corcoran was now a senior figure in the Brotherhood and was one of its five-member central committee. The Legion took part in the battles of the Nansemond river and Suffolk (April 1863) and held in check the advance of the enemy on Norfolk. In total three-and-a-half thousand men served in the Legion, of which 800 were killed in action, 900 wounded, and four received the congressional medal of honour.
Corcoran himself did not live out the war. In April 1863 he was involved in an outpost incident in Virginia in which he shot and killed Lt.-col. Edgar A. Kimball of the 9th Regiment, New York Volunteers (Hawkins's Zouaves). The incident discredited Corcoran and he was ordered to face a court martial, which was, however, never convened. A subsequent report in Blackwood's Magazine (May 1867) suggested that he was drunk at the time. This was strongly denied by Thomas Clarke Luby (qv), who was present in the camp, but he may have been protecting a fellow Fenian. It was also suggested that drink played a part in Corcoran's own death seven months later, on 22 December 1863 near Fairfax Court House, Virginia, after an accidental fall from a horse, when he was riding with T. F. Meagher (qv). He seems to have died from a brain haemorrhage, rather than the fall. His body was brought to New York, where it lay in state in the city hall before burial in Calway cemetery, Long Island. The knights of Columbanus, together with the 69th, placed a memorial tablet to Corcoran on the wall of the 69th Regiment armoury on Lexington Avenue in January 1914; and in 1990 a new gravestone was erected to him.