Since 2009 he has served as the of the Spanish Government, until 2011, and between 2000 and 2012 as the Chairman of Partido Socialista Obrero Español (Spanish Socialist Workers' Party). From 1990 to 2009 he was the President of the Regional Government of Andalusia. He is a trustee of the Fundacion IDEAS, Spain"s Socialist Party"s think tank. Chaves entered national politics in 1977 when he was elected to the Spanish Congress of Deputies, representing Cádiz serving in Congress until 1990.
Manuel served as the Minister of Work and National Health Service (Seguridad Social) of Spain between 1986 and 1990, under Prime Minister Felipe Gonzalez.
In 1988, he suffered a general strike (first in the current Spanish democracy) call by, among others, the UGT and CCOO due to a proposed law change. In 1990, he became president of the Regional Government of Andalusia.
At the time he was considered to be one of three barons of the Partido Socialista Obrero Español (Spanish Socialist Workers' Party), together with Juan Carlos Rodríguez Ibarra and José Bono, who were also autonomous presidents. After the defeat of his party in the general election of 12 March 2000, after which Joaquín Almunia resigned as General Secretary of the party, Manuel took charge of the Political Commission.
He organized the 35th Congress of the Partido Socialista Obrero Español (Spanish Socialist Workers' Party), which elected José Luis Rodríguez Zapatero as General Secretary.
In April 2009, Prime Minister Zapatero designated Chaves as of the Government and Minister of Territorial Policy (the former Ministry of Public Administrations).