Larkin, Denis (1908–87), trade unionist and politician, was born 8 June 1908 in Rostrevor, Co. Down, the second of four sons of the legendary Irish trade unionist James Larkin (qv) and Elizabeth Larkin (née Brown), the daughter of a lay baptist preacher from Co. Down. After the family moved to Dublin in 1909, Denis, along with his brother James (qv) attended Patrick Pearse's (qv) St Enda's school in Rathfarnham, Co. Dublin, which he found austere, but given his father's reputation, it was the only school that would accept them.
After leaving school, Denis worked in a variety of jobs, including the London Across Trading Concern. In 1928 he became an official with the WUI (founded by his father in 1924), and had to contend with a multitude of strikes in the coal, gas, building and victualling industries. As the WUI expanded during the 1940s, Denis became involved in many hearings and presentations at the Labour Court, and in 1949 became district branch secretary of the union and an executive member of the Irish Trades Union Congress (ITUC), working closely with his brother James, then general secretary of the WUI, although he did not share his brother's communist sympathies.
Active in the political side of the labour movement, he was a member of the Labour party's administrative executive from 1931. An unsuccessful Labour candidate in the general election of 1951, he was elected TD for Dublin North East (1954–61) and frequently deplored the failure of the 1954–7 coalition government to deal with the unemployment problem. A member of Dublin corporation for thirty years, he was chairman of the housing committee of the corporation where he sought a solution to Dublin's housing crisis, and in 1955 with the support of Robert Briscoe (qv), leader of Fianna Fáil on the corporation, he was elected lord mayor of Dublin. As well as being the first representative of the ITUC to attend the International Conference of Unions since the trade union split on world affiliation in 1945, he was a member of the European Trade Union Confederation Executive, and the only trade union representative on the European Special Committee to Combat Poverty. When his brother James died in 1969, Denis became general secretary of the WUI, and although it was a difficult task to follow in his brother's footsteps, he presided over a period of expansion of the union. Serving as vice-president of the ICTU (1973–4) and president (1974–5), he regarded his greatest achievement as leading Irish trade unions in the 1974 national agreement, where he secured a commitment to an annual pay increase of 23.5%.
A more gregarious character than his brother James, he was regarded as an outstanding negotiator and a pragmatist who believed that resorting to strike action marked a failure on the part of union negotiators. Elected to the dáil again for Dublin North East (1965–9), he displayed a strong social conscience, with a particular concern for housing and health care. He also had an astute political sense and was not in principle opposed to the participation of the Labour party in coalition government. A resolute opponent of republican violence, he was disappointed that the political wing of the labour movement was not as strong as the industrial.
He retired from the general secretaryship of the WUI in April 1977, enabling him to pursue his love of photography. He died 2 July 1987 in Dublin, some years after the death of his wife Anne Moore, a native of Dublin and fellow party activist who had been his agent on election campaigns. They had two children, Stella, and Jim, who also became a trade unionist.