Spanish engineer, philosopher, and politician. He studied Industrial Technical Engineering at the Escuela de Peritos (Institute of Experts) of Seville, where he worked until 1975 as a drawing teacher. Later, he completed his training with a degree in Philosophy and Letters at the University of Seville, where he met Felipe González and began to develop his political activism.

He joined the Juventudes Socialistas (Socialist Youth) of Seville in 1960 and joined the Partido Socialista Obrero Español (PSOE/Spanish Socialist Worker's Party) two years later, being a member of the Federación Socialista de Andalucía (Socialist Federation of Andalusia). In 1970 he joined the executive committee of the party.

In those years of political clandestinity for the formations facing the Franco regime, Guerra, who responded to the nickname of Andrés, and along with Felipe González, was one of the most important figures of the XXIV Congress of the PSOE. It was held in Toulouse in 1970 and was scene of the first disagreements between the so‑called 'historical' socialists who lived in exile and the 'renovators' of the interior of the country.

He was consolidated within the leadership of the party with Felipe González in 1974, during the celebration of the XXVI Congress of the PSOE held in the French city of Suresnes.

He was elected deputy in the successive parliamentary elections since 1977, being deputy uninterrupted since the beginning of democracy in Spain until January 2015. His participation in the drafting of the Spanish Constitution of 1978, together with Abril Martorell, was essential for the consensual achievement of its approval.

When the XXXIV Congress was held in June 1997, Joaquín Almunia was elected the new Secretary‑General of the PSOE and the vice‑secretary was eliminated from the organizational chart. Away from the new Socialist Executive, Alfonso Guerra accepted the presidency of the Pablo Iglesias Foundation, three months later.

He described himself as a lover of literature in general, and of poetry in particular. His passion for letters was born in his university stage, where he directed some plays for independent groups and participated in the launch of literary magazines, such as El Palaustre, La Trinchera and the poetic collection El Bardo. In 1969 he founded the Antonio Machado bookstore in Seville, a meeting place for politicians and intellectuals. Later he took over the chairmanship of the Editorial Board of the publication Temas para el Debate. He is the author of poems, articles, and a good number of political works (Perspectivas de una España Democrática, El futuro del socialismo, El nuevo compromiso europeo, La democracia herida, Socialismo y cultura, etc.). He is 'hijo predilecto' (favourite son) of Andalusia since 2011.