Born in Liverpool, Tom Johnson worked on the docks for an Irish fish merchant, spending much of his time in Dunmore East and Kinsale. It was this way that he picked up ideas about socialism and Irish nationalism, joining in 1893 a Liverpool branch of the Independent Labour Party. In 1900 he started work as a commercial traveller, then moved in 1903 with his family to Belfast where he became involved in trade union and labour politics.
Labour activist
In 1907 Johnson helped James Larkin organise a strike in the port, but had to watch in dismay as the strike, which began with remarkable solidarity between labour, Orange, and nationalist supporters, collapsed in sectarian rioting. At various times he was the president, treasurer and secretary of the Irish Trades Union Congress which was, at that time, also the Labour Party in Ireland, until officially founded in 1912 by James Connolly and James Larkin. Johnson became Vice-president of TUC in 1913, and President in 1915. Johnson sympathized with the Irish Volunteers, many of whom were sacked from their jobs, for illegal activities. During the Easter Rising, he noted in his diary that people in Ireland paid little heed to the fate of the defeated revolutionaries. He succeeded as leader of the Labour Party from 1917, when the party did not contest the 1918 general election. When the British government tried to enforce conscription in Ireland in 1918, Johnson led a successful strike in conjunction with other members of the Irish anti-conscription movement.
Johnson is the only Leader of the Labour Party who served as Leader of the Opposition in the Dáil. He lost his Dáil seat at the September 1927 general election, and the following year he was elected to Seanad Éireann, where he served until the Seanad's abolition in 1936. In 1896 he met Marie Tregay, then a teacher in St. Multose's National school, outside Kinsale. A native of Cornwall she had advanced political views. They married in 1898 in Liverpool. Their only son born in 1899, Thomas James Frederick, became a well-known actor. Thomas Johnson died on 17 January 1963 at 49 Mount Prospect Avenue, Clontarf, Dublin. Each Summer, Labour Youth holds the "Tom Johnson Summer School" to host panel discussions, debates and workshops.