The regiment including the 100th Infantry Battalion is best known as the most decorated in U.S. military history,[4] and as a fighting unit composed almost entirely of second-generation American soldiers of Japanese ancestry (Nisei) who fought in World War II.

[5] In 2010, Congress approved the granting of the Congressional Gold Medal to the 442nd Regimental Combat Team and associated units who served during World War II,[15] and in 2012, all surviving members were made chevaliers of the French Légion d'Honneur for their actions contributing to the liberation of France and their heroic rescue of the Lost Battalion.

Nearly a century later, "the "Remember Pearl Harbor" 100th Infantry Battalion, and the "Go For Broke" 442d Regimental Combat Team is still the most decorated unit in U.S. military history.

General of the Army George C. Marshall praised the team saying, "they were superb: the men of the 100/442d... showed rare courage and tremendous fighting spirit... everybody wanted them."

Shortly after the Imperial Japanese Navy's attack on Pearl Harbor on 7 December 1941, Japanese-American men were initially categorized as 4C (enemy alien) and therefore not subject to the draft.

In March 1942, Lieutenant General John L. DeWitt, head of the Western Defense Command and Fourth Army, issued the first of 108 military proclamations that resulted in the forced relocation from their residences to guarded concentration camps of more than 110,000 people of Japanese ancestry from the West Coast, the great majority of the ethnic community.

General Emmons, worried about the loyalty of Japanese-American soldiers in the event of a Japanese invasion, recommended to the War Department that those in the 298th and 299th regiments be organized into a "Hawaiian Provisional Battalion" and sent to the mainland.

[24] Colonel Charles W. Pence, a World War I veteran and military science professor, commanded the regiment until he was wounded during the rescue of the "Lost Battalion" in October 1944.

[29] With all four machine gun nests down, the 232nd spent around 8 and a half hours defusing landmines and removing fallen trees from the road before allied infantry could push forward.

During the Champagne campaign, the 232nd found themselves in a different setting where they were able to recover a two-man enemy submarine out of the water that was primarily used for reconnaissance and firing torpedoes at allied ships.

Many men deemed proficient enough in the Japanese language were approached, or sometimes ordered, to join the Military Intelligence Service (MIS) to serve as translators/interpreters and spies in the Pacific, as well as in the China Burma India Theater.

[33] In late 1943 and early 1944, calls for replacements for the 100th Infantry Battalion began to come in after the unit became embroiled in fierce fighting during the Allied invasion of Italy and the subsequent Battle of Monte Cassino.

The stubborn desire of the men to close with a numerically superior enemy and the rapidity with which they fought enabled the 100th Infantry Battalion to destroy completely the right flank positions of a German Army....

[citation needed] On 15 July the Antitank Company was pulled from the frontlines and placed with the 517th Parachute Infantry Regiment, 1st Airborne Task Force.

[41][dead link‍] The Southern France Campaign, 15 August to 14 September, led the 442nd to its second Presidential Unit Citation for invading in gliders and the Combat Infantryman Badge for fighting with the infantrymen of the 7th Army.

[39]: 56–57  After many rough landings by the gliders, hitting trees or enemy flak, they held their positions for a few days until relieved by Allied troops coming in by sea.

"[43] After leaving Naples, the 442nd landed in Marseille on 30 September and for the next few weeks they traveled 500 miles (800 km) through the Rhone Valley, by walking and by boxcar, until 13 October.

[citation needed] After heavy fighting dealing with enemy machine guns and snipers and a continuous artillery barrage placed onto the Germans, the 100th Battalion was eventually able to take Hill A by 3 a.m. on 18 October.

Rainfall, snow, cold, mud, fatigue, trench foot, and even exploding trees plagued them as they moved deeper into the Vosges and closer to the German frontlines.

Colonel Rolin's grenadiers put up a desperate fight, but nothing could stop the Nisei rushing up the steep slopes, shouting, firing from the hip, and lobbing hand grenades into dugouts.

[24]: 99  The 522nd became a roving battalion, supporting nearly two dozen army units along the front traveling a total of 1,100 miles (1,800 km) across Germany and accomplishing every objective of their fifty-two assignments.

[39]: 105–7 On the Italian Front, the 442nd had contact with the only segregated African-American active combat unit of the U.S. Army in Europe, the 92nd Infantry Division, as well as troops of the British and French colonial empires (West and East Africans, Moroccans, Algerians, Indians, Gurkhas, Jews from the Palestine mandate)[66] and the non-segregated Brazilian Expeditionary Force[67] which had in its ranks ethnic Japanese.

Clark had to negotiate for the return of the 100th and 442nd because Eisenhower wanted them for the Battle of the Bulge and General Devers, commander of the Sixth Army Group, needed fresh troops.

[citation needed] The Nisei drove so hard that beginning on 17 April the Germans decided to destroy their fortifications and pull back to make a final stand at Aulla.

[73] On 5 October 2010, Congress approved the granting of the Congressional Gold Medal to the 442nd Regimental Combat Team, the 100th Infantry Battalion, and Nisei serving in the Military Intelligence Service.

[74] In 2012, the surviving members of the 442nd RCT were made chevaliers of the French Légion d'Honneur for their actions contributing to the liberation of France during World War II and their heroic rescue of the Lost Battalion outside of Biffontaine.

[79] The Go For Broke Monument in Little Tokyo, Los Angeles, commemorates the Japanese Americans who served in the United States Army during World War II.

Dedicated in 1998, the "Brothers In Valor" memorial at Fort DeRussy in Honolulu, HI, honors the Japanese American veterans who served in World War 2 with the 100BN/442RCT, 1399BN, and MIS.

[81] On November 17, 2020, the United States Postal Service (USPS) announced they would release in 2021 a postage stamp honoring the contributions of Japanese American soldiers, 33,000 altogether, who served in the U.S. Army during World War II, following a multi-year nationwide campaign.

However, the unit's exemplary service and many decorations did not change the attitudes of the general population in the continental U.S. towards people of Japanese ancestry after World War II.