Irish politician who was prime minister of Ireland from 1966 to 1973 and from 1977 to 1979.

Lynch studied law and entered the civil service (Department of Justice) in 1936. He eventually decided on an active legal career, was called to the bar (1945), resigned from the civil service, and practiced on the Cork circuit. He entered politics as a member of the opposition in 1948 and worked closely with Eamon De Valera (de Valera, Eamon). After his party, Fianna Fáil, came to power in 1951, he was a parliamentary secretary in 1951–54, minister for the Gaeltacht (Gaelic-speaking districts) in 1957, minister for education in 1957–59, minister for industry and commerce in 1959–65, and minister for finance in 1965–66.

When Sean Lemass (Lemass, Sean F) announced his retirement as taoiseach (prime minister) in 1966, the result was an internal party conflict over the succession that led to Lynch's selection as a compromise candidate. In November he became head of Fianna Fáil and prime minister. In 1969 Lynch played an important role as civil unrest mounted in Northern Ireland. He steered a middle course during this period: he allowed the Irish army to provide medical treatment to Roman Catholics injured in Ulster who were afraid to seek treatment there, but he fired two cabinet ministers who were suspected of involvement in smuggling arms into Northern Ireland and he did not permit the army of Ireland to intervene in the north.

In 1972 Lynch secured a successful referendum on Ireland's entry into the European Economic Community, and on January 1, 1973, Ireland became a member. Though favouring the unity of Ireland and Northern Ireland, Lynch took a tough attitude toward the terrorist activities of the Provisional Irish Republican Army (IRA), arresting several members over the years. Defeated in the 1973 elections, his party returned to power after the 1977 elections. In December 1979, however, discouraged about his party's prospects, Lynch resigned his leadership and soon after retired from politics. He served on a number of corporate boards after his retirement.