Hilliard, Michael Leo (1903–82), revolutionary and politician, was born 11 March 1903 in Flower Hill, Navan, Co. Meath, fifth child of James Hilliard, a prosperous farmer and cattle dealer, and Mary Hilliard (née O'Brien). Educated at St Finian's College, Mullingar, he left in 1920 to take part in the IRA's independence campaign. A company captain in 4th Battalion, 2nd Meath Brigade, in 1920 he was involved in enforcing the Belfast boycott and in April 1921 was promoted to brigade intelligence officer. His brother James was a battalion quartermaster in the IRA. Taking the anti-treaty side in the civil war, Michael Hilliard was a brigade adjutant in charge of an active service unit in the Meath IRA. He was arrested twice during the civil war, on one occasion escaping through a hole in the wall of Dundalk jail. Rearrested and imprisoned in the Curragh, he went on hunger strike for twenty-six days.
He remained active in the IRA until about 1932, when he left to join Fianna Fáil. From 1934 he represented the party on Navan UDC and the military service registration board. First elected to Dáil Éireann at the 1943 general election, he was reelected at every election until 1973, representing the constituencies of Meath–Westmeath (1943–8) and Meath (1948–73). During his parliamentary career he served as a Fianna Fáil assistant whip and a member of the dáil committee on procedures and privileges, and acted as director of elections in Meath for the presidential campaigns of Seán T. O'Kelly (qv) and Éamon de Valera (qv). Appointed parliamentary secretary to the minister for industry and commerce, Seán Lemass (qv), in 1958, he was promoted to full cabinet rank the following year when he was made minister for posts and telegraphs, a post he held until 1965 and in which role he oversaw the introduction of television, modernised the telephone system, established an advisory committee on stamps, and encouraged the adoption of satellite links. He later held the post of minister for defence from 1965 to 1969, when he stood down as a minister. From January 1973 he served briefly as a member of the nominated European parliament and of the EEC's agricultural committee, but had to resign these positions when he lost his dáil seat in the February 1973 general election, after which he retired from politics. His son Colm was Fianna Fáil TD for Meath (1982–97). In the 1948 general election his brother James stood unsuccessfully for Clann na Poblachta in Meath.
Outside politics, Hilliard was also a farmer and cattle dealer. He lived in Navan at Academy St. and later at 11 St Enda's Villas, where he died 3 August 1982. He married (25 August 1925) Kate, daughter of Peter McMahon, farmer; they had five sons and five daughters.