After receiving his Doctor of Science and eventually his Habilitation in 1909, he worked as an associate professor at the TU Karlsruhe until 1914, when he volunteered for service in World War I.
Together with chemical engineer Wilhelm Lommel, Steinkopf developed a method for the large-scale production of bis(2-chloroethyl) sulfide, commonly known as mustard gas.
Succeeding Reinhold von Walther [de] as the associate professor in organic chemistry at the Technische Universität Dresden, he worked there from 1919 until his retirement.
After the Machtergreifung of the National Socialists in 1933, Reichswehrminister Werner von Blomberg demanded the Saxonian Volksbildungsministerium (Ministry of the People's Education) to show more recognition for Steinkopf's work during World War I.
His health being fragile due to his work with mustard gas and related substances, Steinkopf died on 12 March 1949 in Stuttgart.