A shekara ta 1940, Friedman ya karbi matsayi a Jami'ar Wisconsin<unk>Madison, amma ya bar saboda bambance-bambance tare da malamai game da haɗin Amurka a yakin duniya na biyu. Friedman ya yi imanin cewa Amurka ta shiga cikin yakin. A shekara ta 1943, Friedman ya shiga Sashen Binciken War a Jami'ar Columbia (wanda W. Allen Wallis da Harold Hotelling suka jagoranci), inda ya yi amfani da sauran yakin duniya na biyu a matsayin masanin ilimin lissafi, yana mai da hankali kan matsalolin makamai, dabaru na soja, da kuma gwaje-gwaje na metallurgical.
1945 shekara