The 32d Hospital Center was originally activated in 26 February 1945 at Hawaii as the 32d Medical  Hospital Center.  It was reorganized and redesignated in 16 July 1945 as the Headquarters and Headquarters Detachment, 32d Hospital Center.  The hospital center was inactivated in 28 February 1946 at Okinawa.

In 1947 it was activated at Detroit, Michigan, after having been allotted to the Organized Reserve (today's Army Reserve) and redesignated as the HHD, 317th Hospital Center.  In 1949 it became just Headquarters, 317th Hospital Center.  The hospital center was inactivated at Detroit, Michigan during 1950. 

 The unit was redesignated in January 1956 as the 317th Convalescent Center, and activated at Kalamazoo, Michigan, where it served until being inactivated in 31 January 1979.  The hospital center has been allotted to Regular Army and redesignated back to the 32d Hospital Center, 20 March 2019 at Fort Polk, Louisiana.

The 115th Field Hospital traces its origin to Evacuation Hospital #15, constituted in the Regular Army on 28 December 1917.  Evacuation Hospital  #15 earned a battle streamer for its participation in the Meuse-Argonne Forest offensive from 26 September through 11 November 1918 during World War I.  Evacuation Hospital #15 was reconstituted as the 15th Evacuation Hospital on 9 November 1936.

As World War II escalated, the 15th reorganized and operated in a number of locations within the North African Theater until just prior to D-Day.  On 20 October 1943, the unit was reorganized and re-designated as the 15th Evacuation Hospital, Semi-mobile. In addition to several campaign streamers, including: Tunisia, Naples-Foggia, Rome Arno, Po Valley, and North Apennines, the 15th Evacuation Hospital Received the Meritorious Unit Citation for its outstanding performance during World War II.

On 21 December 1973, the 15th Evacuation Hospital was officially designated the 15th Combat Support Hospital. On 16 March 1984, after nine years of distinguished service, the 15th Combat Support Hospital was appointed as the 15th Evacuation Hospital.

From 8 January 1991 to 26 April 1991, the hospital deployed to Saudi Arabia in support of Operations Desert Shield/Desert Storm. On 16 October 1994, the 15th Evacuation Hospital was reassigned as the 115th Field Hospital. The 115th deployed to Bosnia-Herzegovina from March to September 2000. In support of Operation Iraqi Freedom, the 115th Field Hospital deployed to Kuwait in 2003 and to Abu Ghraib Prison in Iraq from July 2004 to July 2005.

In October 2005, the 115th Field Hospital transitioned to a Combat Support Hospital. From May 2008 to August 2009, the 115TH CSH deployed again to Iraq. For the year 2011, the 115TH CSH deployed to Camp Dwyer, Afghanistan. The most recent deployment in support of Operations Spartan Shield and Inherent Resolve resulted in the unit performing quality healthcare and expeditionary damage control surgery across the Central Command Area of Ops (AOR) to include elements in Kuwait, Iraq, Jordan, and Egypt.

The 115th Field Hospital has a long and honorable history - one that reflects great credit upon its members, both past and present.