Guido Sacconi studied philosophy at the University of Florence. In 1972 he became Responsible for the research office at the Chamber of Labour of Florence. In 1978 he was appointed General Secretary of FIOM-CGIL. In 1990 he was appointed General Secretary of the Chamber of Labour of Florence. Two years later, he became Regional Secretary of the Democratic Party of the Left.
Between 1999 and 2009, Guido Sacconi served as a member of the European Parliament. During that time he was member of the Group of the Party of European Socialists, member of the Socialist Group in the European Parliament, Chair of the Temporary Committee on Climate Change, Vice-Chair of the Committee on the Environment, Public Health and Consumer Policy, member of the Committee on the Environment, Public Health and Consumer Policy, member of the Delegation to the EU-Turkey Joint Parliamentary Committee, member of the Committee on Petitions, member of the Committee on the Environment, Public Health and Food Safety, member of the Delegation for relations with the People's Republic of China, member of the Delegation to the EU-Russia Parliamentary Cooperation Committee, member of the Temporary Committee on Climate Change and member of the Conference of Committee Chairs.