As a medical doctor specializing in pharmacology and a native German speaker, Carlo Henze served as a Captain in the U.S. Army Medical Corps. He was assigned as a medical intelligence officer to the top-secret Alsos Mission in Europe, whose goal was to determine German progress in developing an atomic bomb and biological and chemical weapons. At times Alsos team members operated behind enemy lines. Carlo's citation for the Legion of Merit mentions his imagination, skill and ingenuity, which made possible the successful completion of an investigation regarding these projects and their possible relationship to comparable Japanese programs. Through his daring and acceptance of risks beyond the call of duty, Captain Henze directed and participated in the location and seizure of secret German records revealing full details of the German research program.

In addition to his official mission in Europe, Carlo had a personal priority - to reunite with his parents in Austria after not seeing them for six years. His father had been a professor of biochemistry at the University of Innsbruck. He lost his job and his pension because he would not allow Nazi uniforms in his classroom. The reunion finally took place two days after VE Day, on May 11, 1945. Carlo's war experience, including the reunion with his parents, was a high point of his life. After the war he resumed work at Sandoz Pharmaceuticals, where he became a Vice President and later, President of the Sandoz Foundation. In his retirement home, he always kept his helmet on a chair beside his bed.