As a member of the Spanish Socialist Workers' Party, he spent the war creating propaganda posters and murals. During the Siege of Madrid, he helped to rescue works from the Museo del Prado, moving them to Valencia, where he settled in 1937. There, he was able to obtain another professorial appointment in Orihuela. This lasted for only a very short time before he moved to Barcelona, where he continued his previous propaganda efforts and taught drawing at the Labor Institute.