Jack H. Smith entered Albany State with the class of 1943, but transferred to Cornell University to focus his studies on mathematics and physics. After completing his undergraduate degree in 1943, he remained at Cornell and entered the graduate physics program. He was almost drafted, but after the intervention of senior scientists in Washington was among those "set aside" to contribute to the war effort as civilians. In 1945, he began work in the Theory Division at Los Alamos, performing calculations as part of America's effort to develop a nuclear bomb.

After the defeat of Japan, he received a certificate and pin, the Army-Navy E for Excellence, in appreciation of his war-time efforts.