Joseph Devlin (13 February 1871 – 18 January 1934) was an Irish journalist and influential nationalist politician. He was a Member of Parliament (MP) for the Irish Parliamentary Party in the House of Commons of the United Kingdom of Great Britain and Ireland, and later a Nationalist Party MP in the Parliament of Northern Ireland.
Born at 10 Hamill Street, in the Lower Falls area of Belfast, he was the fifth child of Charles Devlin (died 1906) who ran a hackney cab, and his wife Eliza King (died 1902) who sold groceries from their home, were both Roman Catholics. Until he was twelve he attended the nearby St. Mary's Christian Brothers' School in Divis Street, where he was educated in a more 'national' view of Irish history and culture than offered by the diocesan schools or the state system.
While working briefly as a clerk and in a pub, he showed an early gift for public speaking  when he became chairman of a debating society founded in 1886 to commemorate the first Irish nationalist election victory in West Belfast. From 1891–1893 he was a journalist on the Irish News, then on the Freeman's Journal when he became associated with the Ancient Order of Hibernians (AOH), which he helped to establish in the 1890s. He became a lifelong opponent of its loyalist counterpart, the Orange Order. He then worked at Samuel Young MP's brewery company, for whom he managed a Belfast pub until 1902.
During the 1890s he was active as organiser in the anti-Parnellite Irish National Federation in eastern Ulster. When William O'Brien founded the United Irish League (UIL) in County Mayo in 1898, Devlin founded the UIL section in Belfast which became his political machine in Ulster. He was elected unopposed as Irish Parliamentary Party (IPP) Member of Parliament for Kilkenny North in the February 1902 by-election. His first political assignment came that year when the Party sent him to Irish Americas on the first of several successful fund-raising missions.
It was there that he encountered the power of the Hibernian Orders and on his return set about claiming it for constitutional nationalism, when in 1904 he became lifelong Grandmaster of the AOH in Ireland. Members of his Order, largely composed of earlier members of the Molly Maguires, a militant secret society also known as the Mollies, also became members of the Irish Party, deeply infiltrating it. Already secretary of the London-based United Irish League of Great Britain Devlin became General Secretary of O’Brien's UIL, replacing John O'Donnell, through the initiative of deputy IPP leader John Dillon MP, with whom he held a close alliance and who had fallen under his influence. This "coup" gave them nationwide control of the 1200 UIL branches, the organisational base of the IPP, depriving O'Brien of all authority.
Devlin had risen in the ranks of the League from being a local Nationalist organiser in Belfast to becoming the only newcomer to the parliamentary party who was accepted politically, as an equal by the established leaders. He was devoted to Dillon who had helped him greatly to his rise to prominence, and Dillon in turn relied greatly on him, not alone for both his control of the UIL and the AOH, but also because he was an outstanding representative of Ulster Nationalism