Born in Sevilla and a baker by trade since age eleven, at 18 joined La Aurora, the Union of Seville bakers, who soon after joined the anarchist Confederación Nacional del Trabajo. He became known as the leader of a strike in 1917 and in 1920 participated in the general strike called by the leadership of the CNT, which ended in failure. After the start of Miguel Primo de Rivera's dictatorship, Díaz continued his labor activism in clandestinity being arrested in Madrid in 1925. In 1927, already out of jail, he joined the Communist Party of Spain (PCE) with much of the leaders of Seville anarchism. He was able to attract the more radical workers, who were disenchanted with the traditional unions, as well as helping the PCE profit from rivalry between the socialistUnión General de Trabajadores and the anarchistConfederación Nacional del Trabajo.
Diaz's health deteriorated due to stomach cancer, and he left Spain for the Soviet Union in November 1938, being operated on in Leningrad. He remained in Moscow after the Republican defeat and the start of World War II, being active as a cadre in the Comintern Secretariat (an overseer of communists in Spain, South America, and British India). Díaz also wrote an essay containing self-criticism, one prompted by the ideological demands of the Great Purge and Stalin's personality cult, entitled Las enseñanzas de Stalin, guía luminoso para los comunistas españoles ("The Teachings of Stalin, a Luminous Guide for the Spanish Communists"). The articles he wrote in the period were collected as Tres años de lucha ("Three Years of Combat").
When the German forces invaded the Soviet state in June 1941, José Díaz was forced to take refuge in Pushkin. In autumn, he settled in Tbilisi (Georgian SSR) but his ailment and the immense pain caused him to take his own life that spring. The circumstances of his death have been disputed ever since, with many believing that he had actually been murdered on Stalin's orders. Notably, the stance Díaz had taken in 1939, when he asked for the PCE to be given full control over the Republican government, went clearly (albeit perhaps unwittingly) against the Stalinist strategy.
The KGB file concerning him was declassified in the 1990s (after the fall of the Soviet Union): it failed to provide any evidence incriminating Stalin's government. Díaz was replaced as general secretary by Dolores Ibárruri.
José Díaz was initially buried in Tbilisi's Vera Cemetery, where a tomb monument authored by the Georgian sculptor Moris Talakvadze was installed. The statue disappeared in the early 1990s and only a tombstone has survived. In April 2005, José Díaz's remains were reburied in Seville, and the PCE honored his memory with a ceremonial; the city's Ayuntamiento unanimously voted to designate him Hijo predilecto ("Favorite son").[3]
His surname became a popular given name in the USSR.
Dallin, Alexander and Firsov, F. I. eds., Dimitrov and Stalin : 1934–1943 : letters from the Soviet archives ;(2000), Yale Univ. Press, New Haven And London, Russian documents translated by Vadim A. Staklo. p. cm. — (Annals of communism) Includes bibliographical references and index. ISBN0-300-08021-2 (alk. paper)
Degras, Jane T., ed. (1956–1965). The Communist International, 1919–1943: Documents. 3 vols. London: Oxford University Press.
Geoff Eley, Prof. of History at the Univ. of Michigan, Forging Democracy: The History of the Left in Europe, 1850–2000, Oxford University Press (2002), paperback, 720 pages, ISBN0-19-504479-7, ISBN978-0-19-504479-9
Kahan, Vilém, ed. (1990). Bibliography of the Communist International (1919–1979). Leiden: E. J. Brill Academic eds. Leyden and New York, 400 pages, ISBN90-04-09320-6
Kahan Vilém, The Communist International, 1919–1943: the Personnel of its Highest Bodies, 352 pages, London: I B Tauris, (2002), ISBN1-86064-747-2
McDermott, Kevin, and Agnew, Jeremy. (1997). The Comintern: A History of International Communism from Lenin to Stalin. XXV + 304 pages, 978-0312162771 New York: St. Martin's Press.
Lazitch, Branko, French speaking Serbian historian and political journalist, (1923–1998), specialist in Soviet History and the International Communist, Biographical Dictionary of the Comintern, (Stanford: Hoover Institution Press, 1973)
