Mezue ahịrịokwu na-esonụ: 15th Infantry hapụrụ China maka Fort Lewis, Washington, na 2 March 1938. Na 12 Jenụwarị 1940, e kenyere ndị agha ahụ na 3rd Infantry Division. LTC Dwight D. Eisenhower jere ozi na 15th site na Machị ruo Nọvemba 1940, dịka onye isi nke 1st Battalion. N'abalị iri abụọ na anọ n'ọnwa Ọktoba n'afọ 1942, ndị 15th Infantry na 3rd Infantry Division siri na Norfolk, Virginia, gawa French Morocco. N'ime ọnwa iri atọ na otu sochirinụ, ndị agha ahụ lụrụ ọgụ na French North Africa, Sicily, Italy, France, na Germany. N'ụbọchị iri nke ọnwa Julaị, ndị agha nke iri na ise nke ndị agha na-amalite na Sicily na Licata na h.2.57,
Ndị Allied wakporo Sicily, nke a kpọrọ Operation Husky, n'ụsọ osimiri Mollarella na Poliscia. Ka ọ na-erule ngwụsị nke agha ahụ na Europe, ndị agha nke 15 nwere ndị nnata 16 nke Medal of Honor gụnyere Audie Murphy, onye agha agha kachasị mma nke Agha Worldwa nke Abụọ. Ọnwụ ndị agha nke iri na ise maka Agha Worldwa nke Abụọ gụnyere, 1,633 gburu, 5,812 merụrụ ahụ, na 419 na-efu na ọgụ.