Puharich was born in Chicago, Illinois, one of seven children born to Croatian immigrants. His father had emigrated from what was then the Austro-Hungarian Empire, entering the U.S. in 1912 as a stowaway. At home Karel's parents always called him "Andrija," which apparently wasn't his name at birth but just his parents' nickname for him. When Karel, as a young boy, started attending school, his parents enrolled him under the name "Henry Karl Puharich," feeling he would be more easily accepted with that name than with the foreign-sounding name "Karel Puharić." Thereafter he often signed his name as "Henry Karl Puharich." He didn't start using his nickname "Andrija" as his first name until sometime in the later part of his life.