Cvjetko Popović was a Serb born in Bosnia and Herzegovina in 1896. He was a student in Sarajevo when Danilo Ilić recruited him and his friend, Vaso Čubrilović to help assassinate Archduke Franz Ferdinand.
Nikola Pašić, the prime minister of Serbia, heard about the plot and gave instructions for the three men to be arrested. However, his orders were not implemented and the three man arrived in Bosnia-Herzegovina where they joined forces with fellow conspirators, Danilo Ilić, Vaso Čubrilović, Gavrillo Princep, Miško Jovanović and Veljko Čubrilović.
On Sunday, 28 June 1914, Franz Ferdinand and Sophie von Chotek were assassinated by Gavrilo Princip. Princip and Nedjelko Čabrinović were captured and interrogated by the police. They eventually gave the names of their fellow conspirators. Muhamed Mehmedbašić managed to escape to Serbia but Popović, Danilo Ilić, Vaso Čubrilović, Veljko Čubrilović and Miško Jovanović were arrested and charged with treason and murder.
All the men were found guilty. Under Austro-Hungarian law, an offender under twenty could not be executed. Nedjelko Čabrinović, Gavrilo Princip and Trifko Grabež therefore received the maximum penalty of twenty years, whereas Vaso Čubrilović were sentenced to 16 years and Popović to 13 years prison at Terezín.
Popović was released when the Allies defeated the Central Powers in November 1918. He returned to teaching and eventually became Curator of the Ethnographic Department of the Sarajevo Museum.