Early political career

Member of the PSC-CVP since its creation in 1945, Harmel was elected deputy for the first time in the parliamentary elections of 17 February 1946. He would keep his seat without interruption until 1971.

Harmel represented Belgium at the fourth session of the General Assembly of the United Nations in 1949. He subsequently was member of several governments in the 1950s and 1960s.

School War

During his period as Minister of Education (8 June 1950 until 22 April 1954), Harmel increased the wages of teachers in private (i.e. Catholic) schools and introduced laws linking the subsidies for private schools to the number of pupils. These measures were perceived by the secularists (i.e. the anti-clerical Liberals and Socialists) as a declaration of war. When the 1954 elections brought to power a coalition of Socialists and Liberals, the new Education Minister, Leo Collard, immediately set out to reverse the measures taken by his predecessor, sparking mass protests by the Catholic bloc. A compromise was eventually found by the next government (a Catholic minority government led by Gaston Eyskens), and the "School War" was concluded by 6 November 1958 School Pact. André Molitor was one of the chief architects of the school pact.

Minister of Justice, Prime Minister and Minister of Foreign Affairs

Harmel was Minister of Justice in the second government led by Gaston Eyskens (23 June 1958 – 6 November 1958), and then Minister of Culture (6 November 1958 – 3 September 1960) and Minister of the Civil Service (3 September 1960 – 25 April 1961) in the third Eyskens cabinet.

Prime Minister of Belgium from 28 July 1965 until 19 March 1966, Harmel led a coalition comprising Christian Democrats and Socialists. Finally, he was Minister of Foreign Affairs in the Liberal-Christian Democratic coalition led by Paul Vanden Boeynants (19 March 1966 – 7 February 1968). As Foreign Minister he chaired the opening meeting of the enlargement negotiations between the EEC and the four applicants for Community membership in June 1970. Indeed, Harmel's opening statement to the enlargement conference has since formed the basis of the Community opening position for future enlargement discussions.

Later career

After 25 years in the Chamber of Deputies, Harmel was Senator from 1971 until 1977. He was made a Minister of State from 1973. In 1988, he was awarded an honorary doctorate at the Catholic University of Louvain, and in 1991, was raised into the Belgian nobility by King Baudouin with the hereditary title of Count Harmel (Dutch: graaf Harmel).