Arthur Griffith was born in Dublin, Ireland on 31 March 1872, of distant Welsh lineage, and was educated by the Irish Christian Brothers. Griffith College Dublin in South Circular Road, Dublin, Griffith Avenue in North Dublin and Griffith Park in Lucan, County Dublin are named after him.
He worked for a time as a printer before joining the Gaelic League, which was aimed at promoting the restoration of the Irish language. His father had been a printer on The Nation newspaper — Griffith was one of several employees locked out in the early 1890s due to a dispute with a new owner of the paper. The young Griffith was a member of the Irish Republican Brotherhood (IRB). He visited South Africa from 1897–1898, after the defeat and death of Charles Stewart Parnell whose more moderate views he had initially supported, while he (Griffith) convalesced from tuberculosis; there he supported the Boers against British expansionism and was a strong admirer of Paul Kruger.
In 1899, on returning to Dublin, he co-founded the weekly United Irishman newspaper with his associate William Rooney, who died in 1901. In 1910, Griffith married his fiancée, Maud, after a fifteen-year engagement; they had a son and a daughter.

Griffith's fierce criticism of the Irish Parliamentary Party's alliance with British Liberalism was heavily influenced by the anti-liberal rhetoric of Young Irelander John Mitchel, the County Londonderry-born son of a Presbyterian minister; Griffith combined fierce hostility to snobbery and deference, as well as a sort of "producerist" attitude based on skilled craft trade unionism, with some strongly illiberal attitudes. He defended anti-semitic rioters in Limerick, denounced socialists and pacifists as conscious tools of the British Empire, and successively praised Tsarist Russia and Wilhelm II as morally superior to Great Britain.

In September 1900, he established an organization called Cumann na nGaedhael to unite advanced nationalist/separatist groups and clubs. In 1903 He set up the National Council to campaign against the visit to Ireland of King Edward VII his consort Alexandra of Denmark. In 1907, this organization merged with Sinn Féin and a number of others movements to form the Sinn Féin (Irish for "We Ourselves"). In 1906, after the United Irishman journal collapsed because of a libel suit, Griffith refounded it under the title Sinn Féin; it briefly became a daily in 1909 and survived until its suppression by the British government in 1914, after which it was sporadically revived as the ultranationalist journal, 'Nationality'.