Chairman of the European Commission from 1985 to 1995, he held important roles in French banking and state planning from the 1940s and in 1968 he became advisor to Prime Minister Jacques Chaban-Delmas. In 1974 he joined the French Socialist Party, and from 1979 to 1981 he served in the European Parliament. He served as Economics, Finance and Budget Minister (1981-84), helping to revive the French economy. With British Commissioner Lord Cockfield, he crafted and won approval for the Single European Act (1986), which laid the groundwork for the creation of a single EC market in 1993. He also had an important role in the transformation of the European Community into the European Union. He is Founding President of the think tank Notre Europe, Honorary Member of the Club of Rome and President of the CERC (Conseil Emploi Revenu Cohésion Sociale).