Dr. Smith's career began while he was a student at the California Institute of Technology (Caltech) in the late Thirties. His was part of a research group whose rocket testing led to the later formation of the National Aeronautics and Space Administration's Jet Propulsion Laboratory in 1944.

He began his career with Douglas Aircraft after receiving master's degrees in both mechanical and aeronautical engineering from Caltech. His early work included wind tunnel testing of several aircraft including the A-20, DC-5 and A-26. While working for Aerojet Engineering Corporation he helped develop rocket boosters to assist propeller planes taking off with heavy bomb loads.

After returning to Douglas he became very involved with the aerodynamic design of the D-558 Phase 1 airplane, a jet powered research airplane pioneering the investigation of the transonic regime of level flight, and world speed record holder. His vast knowledge of the physics of fluid flow helped him lead the development of the field now known as computational fluid dynamics.

Smith was the recipient of numerous honors and awards, including an honorary doctorate degree from the University of Colorado, the Casey Baldwin award and the Robert H. Goddard Award. He was a member of the National Academy of Engineering.