Along with Frank Whittle, one of the inventors of jet propulsion.
Having earned a PhD in Physics and Aerodynamics from the University of Gottingen, Ohain obtained a patent on his jet engine plans in 1936. He was then sponsored by Ernst Heinkel to develop a successful liquid-fuelled engine, designated HeS.3B. Heinkel's firm designed an experimental aircraft for the engine, the Heinkel He178, and this made the first jet powered flight in the world on 27 August 1939 near Rostock, Germany.
In 1947, Ohain was taken to the USA under the auspices of the American 'Operation Paperclip', which sought to harness the expertise of scientists and engineers who had worked under the defeated Nazi regime. In 1956 he became Director of the US Air Force Aeronautical Research Laboratory, and by 1975 he was the Chief Scientist of the Aero Propulsion Laboratory there.