From 1893 Larkin had developed an interest in socialism, and he became a member of the Independent Labour Party. In 1905 he was one of the few foremen to take part in a strike on the Liverpool docks. He was elected to the strike committee, and although he lost his foreman's job as a result, his performance had so impressed the National Union of Dock Labourers (NUDL) that it appointed him a temporary organiser. He later gained a permanent position with the union, and in 1906 it sent him to Scotland, where he successfully organised workers in Preston and [[Glasgow].
In 1908 Larkin moved south and organised workers in Dublin, Cork and Waterford with considerable success. His involvement, against union instructions, in a dispute in Dublin resulted in his expulsion from the NDLU. The union later prosecuted him for diverting union funds to give strike pay to Cork workers engaged in an unofficial dispute. After trial and conviction in 1910 he would serve three months in prison for this, a sentence widely regarded as unjust.
After his expulsion from the NDLU, Larkin founded the Irish Transport and General Workers' Union (ITGWU) at the end of December 1908. The organisation still exists today as the Services Industrial Professional & Technical Union (SIPTU). It quickly gained the affiliation of the NDLU branches in Dublin, Cork, Dundalk and Waterford, while the Derry and Drogheda branches stayed with the British union and Belfast split along sectarian lines. Early in the new year, Larkin moved to Dublin, which became the main base of the ITGWU and the focus of all his future union activity in Ireland.
In June 1911 Larkin established a newspaper, The Irish Worker, to provide a pro-labour alternative to the capitalist-owned press. This organ was characterised by a campaigning approach and the harsh denunciation of unfair employers and of Larkin's political enemies. Its columns also included pieces by intellectuals. The paper was produced until its suppression by the authorities in 1915. After that the papers went on to form the new Ireland Echo
In partnership with James Connolly, Larkin helped form the Irish Labour Party in 1912. Later that year he was elected to the Dublin Corporation. However, he did not hold his seat long, as a month later he was removed on account of his fraud conviction.
In early 1913 Larkin achieved some notable successes in industrial disputes in Dublin, making frequent recourse to sympathetic strikes and blacking (boycotting) of goods. Two major employers remained non-union firms and a target of Larkin's organising ambitions: Guinness and the Dublin United Tramway Company.
Guinness staff were well-paid and enjoyed generous benefits from a paternalistic management, and as a result they showed little interest in trade unions. This was far from the case on the tramways. The chairman of the Dublin United Tramway Company, industrialist and newspaper proprietor William Martin Murphy, was determined not to allow the ITGWU to unionise his workforce. On 15 August he dismissed forty workers he suspected of ITGWU membership, followed by another 300 over the next week. On 26 August the tramway workers officially went on strike. Led by Murphy, over four hundred of the city's employers retaliated by requiring their workers to sign a pledge not to be a member of the ITGWU and not to engage in sympathetic strikes.
The resulting industrial dispute was the most severe in Ireland's history. Employers in Dublin engaged in a lockout of their workers when the latter refused to sign the pledge, employing blackleg labour from Great Britain and elsewhere in Ireland. Dublin's workers, amongst the poorest in the then United Kingdom, were forced to survive on generous but inadequate donations from the British Trades Union Congress (TUC) and other sources in Ireland, distributed by the ITGWU.
For seven months the lockout affected tens of thousands of Dublin's workers and employers, with Larkin portrayed as the villain by Murphy's three main newspapers, the Irish Independent, the Sunday Independent and the Evening Herald. Other leaders in the ITGWU at the time were James Connolly and William X. O'Brien, while influential figures such as Pádraig Pearse, Countess Markievicz and William Butler Yeats supported the workers in the generally anti-Larkin media.
The lockout eventually concluded in early 1914 when the calls for a sympathetic strike in Britain from Larkin and Connolly were rejected by the British TUC. Although the actions of the ITGWU and the smaller UBLU were unsuccessful in achieving substantially better pay and conditions for the workers, they marked a watershed in Irish labour history. The principle of union action and workers' solidarity had been firmly established. Perhaps even more importantly, Larkin's rhetoric, condemning poverty and injustice and calling for the oppressed to stand up for themselves, made a lasting impression.
Larkin was also recruited by Imperial German diplomats in New York City into helping sabotage Allied munitions shipments. In the aftermath of the First World War, he would describe his espionage career in detail to the American lawyers investigating the Black Tom Explosion.
Larkin's speeches in support of the Soviet Union, his association with founding members of the American Communist Party, and his radical publications made him a target of the "Red Scare" that was sweeping the nation; he was jailed in 1920 for 'criminal anarchy' and was sentenced to five to ten years in Sing Sing prison. In 1923, he was pardoned and later deported by Alfred E. Smith, Governor of New York.
In September 1923 Larkin formed the Irish Worker League (IWL), which was soon afterwards recognised by the Comintern as the Irish section of the world communist movement. In 1924 Larkin attended the Comintern congress and was elected to its executive committee. However, the League was not organised as a political party, never held a general congress and never succeeded in being politically effective. Its most prominent activity in its first year was to raise funds for imprisoned members of the Anti-Treaty IRA.
During Larkin's absence at the 1924 Comintern congress (and apparently against his instructions), his brother Peter took his supporters out of the ITGWU, forming the Workers' Union of Ireland (WUI). The new union quickly grew, gaining the allegiance of about two thirds of the Dublin membership of the ITGWU and of a smaller number of rural members. It affiliated to the pro-Soviet Red International of Labour Unions. However, like the IWL, the WUI would be hampered in its growth by Larkin's chaotic and dictatorial approach.
In January 1925, the Comintern sent British communist activist Bob Stewart to Ireland to establish a communist party in cooperation with Larkin. A formal founding conference of the Irish Worker League, which was to take up this role, was set for May 1925. A fiasco ensued when the organisers discovered at the last minute that Larkin did not intend to attend. Feeling that the proposed party could not succeed without him, they called the conference off as it was due to start in a packed room in the Mansion House in Dublin.
In the September 1927 general election, Larkin ran in North Dublin and was elected. This was to be the only time that a self-proclaimed communist was elected to Dáil Éireann until the election of Joe Higgins in 1997. However, as a result of a libel award against him won by William O'Brien, which he had refused to pay, he was an undischarged bankrupt and could not take up his seat.
Larkin was unsuccessful in his attempts in the following years to gain a position as a commercial agent in Ireland for the Soviet Union, and this may have contributed to his disenchantment with the communist cause. The Soviets, for their part, were increasingly impatient with his ineffective leadership. From the early 1930s Larkin drew away from the Soviet Union. While in the 1932 general election he stood without success as a communist, in 1933 and subsequently he ran as "Independent Labour". During this period he also engaged in a rapprochement with the Catholic Church. In 1936 he regained his seat on Dublin Corporation. He then regained his Dáil seat in the 1937 general election but lost it again the following year. In this period the Workers' Union of Ireland also entered the mainstream of the trade union movement, being admitted to the Dublin Trades Council in 1936, although the ICTU would not accept its membership application until 1945.
In 1941 a new trade union bill was published by the Government. Inspired by an internal trade union restructuring proposal by William O'Brien, it was viewed as a threat by the smaller general unions and the Irish branches of British unions (known as the 'amalgamated unions'). Larkin and the WUI played a leading role in the unsuccessful campaign against the bill. After its passage into law he and his supporters successfully applied for admission to the Labour Party, where they were now regarded with more sympathy by many members. O'Brien in response disaffiliated the ITGWU from the party, forming the rival National Labour Party and denouncing what he claimed was communist influence in Labour. Larkin later served as a Labour Party deputy in Dáil Éireann (1943–44).
James Larkin died in his sleep on 30 January 1947. His funeral mass was celebrated by the Catholic Archbishop of Dublin, John Charles McQuaid, and thousands lined the streets of the city as the hearse passed to Glasnevin Cemetery.
The Dubliners - James Larkin
Les grands ne sont grands que parce que nous sommes à genoux: Levons-nous.
Ní uasal aon uasal ach sinne bheith íseal: Éirímis.
The great appear great because we are on our knees: Let us rise.
The slogan appeared on the masthead of the Workers' Republic, founded by James Connolly in Dublin in August, 1898. Originally the organ of the Irish Socialist Republican Party, this periodical later became the official organ of the Communist Party of Ireland that was founded in 1921. The original slogan is usually attributed to Camille Desmoulins (1760-1794), the French revolutionary.
On the west side of the base of the Larkin monument is a quotation from the poem Jim Larkin by Patrick Kavanagh:
And Tyranny trampled them in Dublin's gutter
Until Jim Larkin came along and cried
The call of Freedom and the call of Pride
And Slavery crept to its hands and knees
And Nineteen Thirteen cheered from out the utter
Degradation of their miseries.
On the east side of the monument there is a quotation from Drums under the Windows by Sean O'Casey:
...He talked to the workers, spoke as only Jim Larkin could speak, not for an assignation with peace, dark obedience, or placid resignation, but trumpet-tongued of resistance to wrong, discontent with leering poverty, and defiance of any power strutting out to stand in the way of their march onward.
A road in Clontarf, North Dublin, is named after him.
A marching band in Liverpool, the James Larkin Republican Flute Band, is named after him. Formed in 1996 by members of the Liverpool Irish Community, it is a fife & drum marching band, that promotes and celebrates Irish music, culture and political pride and awareness on Merseyside.