Klapka was born at Temesvár, Kingdom of Hungary on 6 April 1820 in a German-speaking family of Moravian origin. His ancestors migrated there from Moravia during the reign of Joseph II (1780-1790) his grandfather founding military pharmacies during the Austro-Turkish War of 1787–1791. In the following decades the families prestige grew, and György Klapka's father, József Klapka, became the mayor of Temesvár for nearly 15 years, being elected for two times deputy in the Hungarian Diet, being later ennobled by the king. His mother was Júlia Kehrer.