Joonas Kokkonen was born the youngest of five children on 13 November 1921 in Iisalmi; the city is almost equidistant between Helsinki and the Arctic Circle. Along with Kokkonen, it is also the birthplace of the renowned Finnish writer and poet Juhani Aho (1861-1921). Kokkonen's family moved to Järvenpää in 1926, a charming city approximately forty kilometers north of Helsinki (Sibelius also lived in the city from 1904 until his death in 1957). A few years after he graduated from the Järvenpää Community School, Kokkonen entered the University of Helsinki, where he studied music history, philosophy and literature. Military service during the early 1940s interrupted his academic study for a couple of years: while Kokkonen spoke little about his war experiences, the horrors he observed as a soldier profoundly shaped the pacifistic sentiments he carried throughout his life (one of Kokkonen's daughters once recounted a humorous story that his lack of aggression was so ingrained that he was even incapable of setting mouse traps for fear of harming a family of mice that had once infested their Helsinki residence). Despite the time spent serving in the war, Kokkonen ultimately received his M.A. degree in music history in 1948. While at the University of Helsinki, however, Kokkonen was simultaneously enrolled at the Sibelius Academy, where he obtained a diploma in piano performance in 1949 (he also studied composition briefly with Selim Palmgren, although Kokkonen would later state that he had learned virtually nothing from him).