Imprisoned in Stalin's Gulags in the 1930s as part of the Great Purge, he later became an ardent Croatian nationalist, anti-communist[1][2] and ideologue of the fascist Ustaše movement.
Coming from a family of Croat peasants, his grandfather shared with the young boy "the interest which he showed in Croatian culture and in the struggles for national emancipation directed against the urban Italian bourgeoisie and the German-Austrian administration".
Intrigued by the October Revolution in Russia, he began a Yugoslav Marxist Club and started editing newspapers such as Komunist and Rudé právo.
In late 1923 he became the chief editor of Borba, KPJ's official gazette, in which he was especially dedicated to debates on the 'national question' and polemics with the 'right-wing' factions of the party whom he accused of defending the Serbian hegemony using a Marxist discourse, which included Sima Marković and Đuka Cvijić among others.
As a dedicated communist activist, he quickly advanced to the level of the Regional Secretary for Croatia-Slavonia, and already in December 1924, the Central Committee of KPJ.
Exiled for his activism from Yugoslavia, he moved to Vienna in 1925 as the local representative of the KPJ and then settled in the Soviet Union, where he lived from October 1926 to December 1935.
Arrested by Stalin's political police, the GPU, because of his opposition to the policies of the Soviet government, he was deported to a labor camp in Siberia.
[2] At the end of 1941, Ciliga returned to the then Independent State of Croatia (NDH), where he was arrested by the Ustashas and imprisoned for one year in the Jasenovac concentration camp.
[6] Having been imprisoned in Stalin's Siberian gulags, Ciliga wrote that what he "experienced there did not even remotely reach the physical, material horrors of Jasenovac.