Born in Malcocinado, Badajoz, Spain, Gonzalez worked as a miner and was a member of a communist party, establishing one of the first militia units to counter Francisco Franco's Nationalist Army upon the outbreak of the Civil War. As a brigade commander, González personally took part in all of the major actions that occurred during the Nationalists' assault on Madrid in 1936. He also commanded formations during the battles of the Corunna Road (December 1936), the Jarama, and Guadalajara (March 1937). In the summer of 1937, he led the 46th Division in the Battle of Brunete. Heavily promoted as a heroic figure by Soviet propaganda, Gonzalez was accused by other officers in the Ejercito Popular of being brutal in his treatment of his men, unsuited for modern battle, and an egomaniac.