Born in Iznajar (Spain) in 1955, Montilla was the first President of the Generalitat born outside of Catalonia. A member of the Socialist Party of Catalonia (PSC) and a local government worker, Montilla was elected mayor of Cornellà in 1985, a post he held until 2004.

From 1988 until 1997 Montilla was president of the Council of Baix Llobregat. In 1983 he became Provincial Councillor and in 2003 he was elected President of the Barcelona Provincial Council and held that position until April of the following year.

In 2004 he led the PSC (Socialist Party of Catalonia) candidature in the general election and shortly after, on April 18, he would become Minister of Industry, Trade and Tourism in the first government of José Luis Rodríguez Zapatero.

After heading the candidacy of Catalan Socialists in elections held in November 2006, he was sworn in as President of the Generalitat of Catalonia by the Plenary Assembly.

During his tenure, President Montilla drove the development of the 2006 Statute of Autonomy, a new funding system, as well as four national agreements on migration, research, housing and infrastructure, through dialogue and participation of major social, economic and political bodies. As of 2008 his government's activity concentrated especially in fighting the effects of the economic crisis and ensuring the cohesion of Catalan society as a whole.