Brendan Corish was born in 1918 in Wexford. He was educated locally and joined the clerical staff of Wexford County Council. He was elected to the Dáil in 1945 in a by-election caused by the death of his father. Between 1948 and 1951 Corish was Parliamentary Secretary to the Ministers for Local Government and Defence. In 1954 Corish was appointed Minister for Social Welfare in the second inter-party government.
In 1960 Corish succeeded William Norton as Labour leader. He introduced new policies which made the party more socialist in outlook. However, the party moved carefully because 'socialism' was still considered a dirty word in 1960's Ireland. Corish claimed that Ireland would be 'Socialist in the Seventies'. To a certain extent he was right because Fine Gael and Labour formed a coalition government between 1973 and 1977. Corish became Tánaiste and Minister for Health and Social Welfare.
In 1977 the coalition went for re-election, however, Fianna Fáil had a landslide vicory. Corish resigned as leader of the Labour party. He retired from politics completely in 1982.
Brendan Corish died on 17 February 1990 in Wexford.