The 156th Infantry was ordered into federal service on 25 November 1940 at home stations. It moved to Camp Bowie, Texas, on 26 February 1942 where it was relieved on 14 July 1942 from assignment to the 31st Division. The 156th arrived in England on 6 October 1942 and the 2nd Battalion, because of the French language abilities of many of its members, was sent to Algeria for military police duties and was redesignated the 202nd Infantry Battalion on 1 September 1943, inactivating on 25 February 1944. The regiment was assigned to the U.S. Army Assault Training Center at Woolacombe, England, and a new 2nd Battalion was activated by shipping the 3rd Battalion, 131st Infantry Regiment to England from Fort Brady, Michigan. The 156th went ashore in France in June 1944 and acted as a separate infantry regiment, performing guard duties at headquarters and supply installations and containing German troops bypassed by allied forces in France. The regiment returned to the United States and was inactivated on 13 March 1946 at Camp Kilmer, New Jersey. Assigned on 28 May 1946 to the 39th Infantry Division, it was reorganized and federally recognized on 18 December 1946 with headquarters at Lafayette.