Csikszentmihalyi was born on 29 September 1934 in Rijeka, then part of the Kingdom of Italy. His family name derives from the village of Csíkszentmihály in Transylvania. He was the third son of a career diplomat at the Hungarian Consulate in Fiume. His two older half-brothers died when Csikszentmihalyi was still young; one was an engineering student who was killed in the Siege of Budapest, and the other was sent to labor camps in Siberia by the Soviets.