Ruiz was born into a Communist Party-supporting family in Orihuela and grew up in the Valencian Community: he himself was a member of the pioneer movement in Spain during his youth. After the defeat of the Republican faction in the Spanish Civil War, his family suffered discrimination in the White Terror for their political views, with his father being banned from formal employment and forced to report to the local police station every two weeks. Being unable to find work, the family milled flour and transported it with a donkey and cart to Valencia to sell.