A lawyer form Seville, joined the PSOE in 1963, where he used the nom de guerre Isidoro. He was a leader of the PSOE from the 1970s, until in the Congress of Suresnes (France) of 1974 when he was elected General Secretary. After the democratic elections of 1977 and 1979, he became the leader of the opposition and a member of the Cortes. After the historical Socialist victory of 1982, he was chosen president of the Spanish Government (Prime Minister), with Alfonso Guerra as vice president, and reelected (although each time with diminishing support) in 1986, 1989 and 1993.
He achieved the abandonment of Marxism by the PSOE and a liberal right-wing economy policy and left-wing social reforms. He supported Spain entering theNATO in a referendum in 1986, reverting his past position, and he supported the USA in First Gulf War in 1991. Under his mandate, Spain joined the EEC. After scandals of corruption and state terrorism (GAL), his party lost the elections of 1996 and he resigned as leader of the party. As of 2003, he is a member of the Cortes but rarely attends sessions.
His wife Carmen Romero is a member of the Cortes for Cádiz.