Karl-Heinrich Riewe was born in Frankfurt, Hesse, Germany, on June 26, 1907, into a German Jewish family. In spite of being born into a Jewish faith, he was a devoted Protestant Christian, as stated in his university job application submitted for the teaching position at the Wesleyan University in Connecticut, United States in 1937. In 1928, he entered in the Technische Hochschule in Charlottenburg (now Technische Universität Berlin) to study mechanical engineering but eventually received his doctorate in physics from the Humboldt University of Berlin in 1936–37. his thesis contained fundamental research on electrical conductivity at high frequency.