Nikola Čolak was born in Janjevo, now the Republic of Kosovo, on 14 April 1914. He was a Croatian historian, classical philologist, philosopher, archivist and publicist. He attended elementary school in his birthplace and the classics gymnasiums in Prizren and Travnik. In 1938, he graduated with a degree in philosophy at Gallarate, near Milan, in Italy. He also earned degrees in the Italian and French languages and literatures in Zagreb in 1943, together with degrees in history and classical philology. A communist court sentenced him to three years of forced labour in Zagreb in 1945 under charges of "plotting an uprising." After being released from the labour camp, he worked in factories on the outskirts of Zagreb and in schools in Ivanić-Grad, Glina and Novi Marof.

From 1954 to 1960, Čolak worked as archivist in the State Archives in Zadar and then moved to the Social Science Institute of the Yugoslav Academy of Arts and Science as a research associate in Zadar (1960-1965). In the summer of 1966, he initiated the review Slobodni glas (Free Voice) together with Mihajlo Mihajlov and a group of intellectuals, the first review that would not be controlled by the one-party state. Because of this initiative, he lost his job at the Institute and had to go into exile to Padua. He taught history and philosophy at Padua University and collaborated with the economic institutes in Verona and Padua. Čolak also joined the ranks of Croatian political émigrés, with particularly intense contacts with the circle around Branimir Jelić and his Croatian National Committee. In 1973, he unsuccessfully tried to renew the activity of the Croatian Party of the Right in exile. Since 1987, he was the assistant to Srećko Pšeničnik, the president of the Croatian Liberation Movement. In exile, he edited two political journals, Hrvatsko pravo (The Croatian Right) and Hrvatska domovina (Croatian Homeland). Čolak also wrote for other émigré journals such as the Hrvatska država (Croatian State), Hrvatska revija (Croatian Review) and Nezavisna država Hrvatska (Independent State of Croatia). He additionally contributed essays and articles about Croatian and Yugoslav matters to Italian newspapers and periodicals such as Il resto del Carlino, Cultura e politica, Il Messaggero, Reggio oggi, and Energie nuove. He established the Centre for Croatian Historical Studies in Padua as a research institution for Croatian history.
As early as 1977, he published his book “Behind Barbed Wire: the Fate of Croatia in Serb-Communist Yugoslavia,” and after that he wrote a new book in Italian in 1979 under the title “Communist Yugoslavia: Between the Intellectual Dissent and Croatia’s Right to Statehood.” In 1988, his book “Croatia Above All: Reflections on the Past and Future Perspectives” appeared, which included Čolak’s essays and articles written during the émigré period of his life. A year later, “The April Tenth Action in Light of the Key Testimony of Ivan Prusac and the Accompanying Documentation” was released. He died at the age of 82 on in Padua on 23 August 1996 and was buried in Zagreb.