In years 1896-1898 he practiced at Benz & Co. He went to college of technology in Hildburghausen for the further apprenticeship and eventually went to Vienna. He became one of the most successful racing drivers in Austria. During the World War I Hieronimus worked as aircraft engine constructor. He died during the accident at Rieß-racing on 8. May 1922, being the head of Steyr-Werke.