Hevesy György was born in Budapest, Hungary, to a wealthy and ennobled family of Hungarian-Jewish descent, the fifth of eight children to his parents Lajos Bischitz and Baroness Eugénia (Jenny) Schossberger (ennobled as "De Tornya"). Grandparents from both sides of the family had provided the presidents of the Jewish community of Pest. His parents converted to Roman Catholicism. George grew up in Budapest and graduated high school in 1903 from Piarist Gimnázium. The family's name in 1904 was Hevesy-Bischitz, and Hevesy later changed his own.
De Hevesy began his studies in chemistry at the University of Budapest for one year, and at the Technical University of Berlin for several months, but transferred to the University of Freiburg. There he met Ludwig Gattermann. In 1906, he started his Ph.D. thesis with Georg Franz Julius Meyer, acquiring his doctorate in physics in 1908. In 1908, Hevesy was offered a position at the ETH Zürich, Switzerland, yet being independently wealthy, he was able to choose his research environment. He worked first with Fritz Haber in Karlsruhe, Germany, then with Ernest Rutherford in Manchester, England, where he also met Niels Bohr. Back at home in Budapest, he was appointed professor in physical chemistry in 1918. In 1920, he settled in Copenhagen.