Flanagan was a social conservative, who famously claimed that "there was no sex in Ireland before television". A notorious anti-semite early in his career, he used his maiden speech in the Dáil, on 9 July 1943, to urge the government to "rout the Jews out of this country".
Nonetheless, he was consistently popular in his own constituency, largely because of the attention he paid to individual voters' petitions and concerns. He has been described as "one of the cutest of cute hoors in the history of the Dáil".
Oliver J. Flanagan was born in Mountmellick, County Laois, on 22 May 1920. He was educated at Mountmellick Boys National School and worked as a carpenter and auctioneer.
Flanagan was secretly a Knight of Saint Columbanus and in 1978 was conferred a Knight of the Order of St. Gregory the Great by Pope John Paul I.
Flanagan first held political office in 1942 when he was elected as a councillor to Laois County Council, a position he would hold for almost forty-five years.
He was first elected to Dáil Éireann in the 1943 general election as a Teachta Dála for the Laois–Offaly constituency — the second youngest person ever to have been elected to the Dáil until that time. He had stood for election on the Monetary Reform Party ticket, an anti-semitic and Social Credit party confined to his own constituency which proposed reducing the supposed Jewish stranglehold on the financial system.
During the campaign, Flanagan wrote to Fr Denis Fahey: "Just a line letting you know we are going ahead with the Election campaign in Laoighis-Offaly against the Jew-Masonic System which is imposed on us. The people are coming to us — but it's hard to get the people to understand how they are held down by the Jews and Masons who control their very lives."
He used his maiden speech in the Dáil to urge the government to "rout the Jews out of this country":
|“||How is it that we do not see any of these [Emergency Powers] Acts directed against the Jews, who crucified Our Saviour nineteen hundred years ago, and who are crucifying us every day in the week? How is it that we do not see them directed against the Masonic Order? How is it that the I.R.A. is considered an illegal organisation while the Masonic Order is not considered an illegal organisation? [...] There is one thing that Germany did, and that was to rout the Jews out of their country. Until we rout the Jews out of this country it does not matter a hair's breadth what orders you make. Where the bees are there is the honey, and where the Jews are there is the money.||”|
—Oliver Flanagan, Dáil Éireann, 9 July 1943.
In 1947 he caused a controversy when he levelled accusations of corruption against members of the Fianna Fáil government, including Taoiseach Éamon de Valera, Minister for Justice Gerald Boland and Minister for Industry and Commerce Seán Lemass. A tribunal of inquiry comprising three judges investigated his allegations and found them to be untrue. Despite the judges' conclusion that Flanagan had lied to the tribunal, his vote increased by 45% in the 1948 general election.
During a 1952 Dáil debate, after John A. Costello had said "I made no reference to an Adoption of Children Bill", Flanagan quipped "Deputy Flynn would be more qualified to do that". John Flynn, who was not in the chamber at the time, interpreted this as an insulting innuendo, and later punched Flanagan in the Dáil restaurant. The Dáil Committee on Procedure and Privilege condemned the conduct of both TDs.
Flanagan joined Fine Gael in 1954. He served in government as a Parliamentary Secretary to the Minister for Agriculture from 1954 to 1957. In 1958, Fine Gael returned to opposition and Flanagan became front bench spokesperson for Lands. In 1975, he was named Parliamentary Secretary to the Minister for Defence.
When Paddy Donegan switched departments following the "thundering disgrace" controversy in 1976, Flanagan succeeded him as Minister for Defence in Liam Cosgrave's government. He served as Minister for six months, until Fine Gael lost power in the 1977 general election.
He was a representative on the Parliamentary Assembly of the Council of Europe from 1977 to 1987.
For reasons of ill-health, Flanagan did not contest the 1987 general election. His son, Charles Flanagan, was elected to his seat. Oliver Flanagan died two months after the election.