William O'Brien (trade unionist)

William O'Brien
O'Brien, c. 1930
Teachta Dála
In office July 1937 – June 1938
In office June 1927 – September 1927
Constituency	Tipperary
In office June 1922 – August 1923
Constituency	Dublin South
Personal details
Born	John William O'Brien (1881-01-23)23 January 1881 Clonakilty, County Cork, Ireland
Died	31 October 1968(1968-10-31) (aged 87) Bray, County Wicklow, Ireland
Resting place	Glasnevin cemetery, Dublin
Political party	National Labour Party (1944–1946) Labour Party (1912–1944)
Occupation	Trade union leader

William O'Brien (23 January 1881 – 31 October 1968) was a politician and trade unionist in Ireland.^[1] While rarely dominating the political spotlight, O'Brien was incredibly powerful and influential behind the scenes, maintaining a firm grip over Ireland's trade unions for many decades. Besides his leadership in the trade unions, O'Brien was a founder, alongside James Larkin and James Connolly, of the Labour Party of Ireland.^[2] In later years a rift formed between Larkin and O'Brien that would last the rest of their lives and often divide the labour movement in Ireland.