Byrne, William Michael (1775–98), United Irishman, was son of Colclough Byrne of Drumquin and a Miss Galway of Cork, a descendant of the 1st duke of Ormond (qv). One of Wicklow's small catholic elite, he lived at Park Hill in the Glen of the Downs and probably joined the United Irishmen in Dublin in 1797. His first cousins Garret (qv) and William Byrne (qv) of Ballymanus and other close relatives in Wicklow and Carlow also became leading rebels at this time. From the spring of 1797 Byrne was the driving force behind the creation of a mass-based revolutionary organisation in northern and central Wicklow, and he was formally returned as a delegate for Rathdown barony. Byrne had joined the Newtownmountkennedy yeomen cavalry in late 1796 but resigned in consequence of a political dispute (October 1797). This occurred around the time that the inaugural meeting of the Wicklow county committee was held at Annacurra in the home of Byrne's first cousin, John Loftus. The committee nominated Byrne as one of their two representatives on the Leinster provincial directory, for whom he liaised with contacts in Munster, particularly in Cork city. He was arrested in possession of incriminating documents at a meeting of the Leinster directory in the house of Oliver Bond (qv) on 12 March 1798 and was tried with Bond for high treason (20 July). Convicted on the evidence of Thomas Reynolds (qv) and others, Byrne was executed 25 July 1798 outside Newgate prison, Dublin. His fate spurred the other United Irish state prisoners in Kilmainham to negotiate a pact with government that secured their lives. Byrne was survived by his wife Rosanna (née Hoey) of the Bray area of Co. Wicklow; they had one daughter, Mary. An oil portrait of Byrne hangs in Aras an Uachtaráin; he was commemorated in 1899 by a relief on the Wicklow town 1798 memorial.
R. R. Madden, The United Irishmen, their lives and times (7 vols, 1842–5), i, iv; Stan O'Reilly, ‘Wicklow rebels of 1798, no. 1: William Michael Byrne’, Wicklow Hist. Soc. Jn., i, no. 7 (July 1994), 16–18; Conor O'Brien, ‘The Byrnes of Ballymanus’, Ken Hannigan and William Nolan (ed.), Wicklow: history and society (1994), 305–40; William Ridgeway, Report of the trial of Michael William Byrne [sic] (1798); The book of the O'Byrnes (1991); Dublin Magazine, Aug. 1798, 92–3; Ruan O'Donnell, ‘General Joseph Holt and the rebellion of 1798 in County Wicklow’ (MA thesis, NUI (UCD), 1991)