During the Morocco wars Aranda earned an outstanding record as an engineer and geographer. He participated in the quelling of the 1934 Asturian revolt and rose to the rank of Colonel. At the beginning of the Spanish Civil War, in 1936, he was in command of the Oviedo garrison, which joined the coup d'etat against the Republic and quickly took control of the city for the Rebel faction. Aranda then successfully defended Oviedo from "miners' militias". For his efforts he was awarded the Cross of San Fernando and promoted to the rank of General. Aranda participated in several further engagements during the war including the Battle of Teruel and the Battle of the Ebro. He served as captain general of the military region of Valencia.