On 14 February 1942, just two months after the American entry into World War II, the 503rd Parachute Infantry Regiment was formed, under the command of Lieutenant Colonel William M. "Bud" Miley.

In May 1942, the 503rd's 2nd Battalion was detached and sailed to Scotland, where it trained and would later take part in the Allied invasion of German-occupied North Africa in November 1942.

Docking in the Panama Canal Zone on 1 November, the 503rd picked up the 501st Parachute Infantry Battalion (minus Company C), which had been undergoing jungle training.

In late 1942 and early 1943, there was confusion about unit designations in the 503rd, as some officers interpreted the 503rd was operating with two 2nd Battalions, one in Australia and one in Great Britain/North Africa.

On 3–4 July 1944, 1st and 3rd Battalions of the 503rd were delivered by parachute to Kamiri Airfield on the island of Noemfoor off the coast of Dutch New Guinea, sustaining significant casualties from the jump.

[2] As a result of his heroic actions during the battle, paratrooper Sergeant Ray E. Eubanks was posthumously awarded the Medal of Honor.

One company of the 503rd RCT engaged in a fierce battle against a company-size Japanese force defending an enemy air raid warning station on the north end of the island.

Braving intense fire, the paratroopers rushed forward and overcame the heavy blockhouse defenses, dropping explosives into embrasures to kill hidden Japanese gunners.

The regimental insignia was designed by Private First Class Thomas M. McNeill while recuperating from his injuries and dengue fever, hepatitis, and malaria on Mindoro Island, following the battle of Corregidor.

After returning to Mindoro, the 503rd was alerted for another combat jump, this time in the central Philippines to reinforce the 40th Infantry Division in its fight on Negros island.

[9] On 26 March 1963 it was assigned to the newly activated 173d Airborne Brigade, and shortly thereafter it was reorganized and redesignated as the 2d Battalion, 503d Infantry on 25 June 1963.

In March 2003, the Turkish government refused to allow American ground forces of the 4th Infantry Division (mechanized), which were positioned at their ports, to move through Turkey in order to establish a northern front in support of "Operation Iraqi Freedom".

Fast-moving Coalition forces were closing on Baghdad with the expectation of having to capture the Iraqi capital from three defensively arrayed divisions.

The oil wealth of the Kirkuk area would be crucial to rebuilding Iraq[citation needed] but the Iraqi army had shown a willingness to destroy their country's own future simply to spite the Coalition.

[citation needed] The troopers integrated forces from fifteen other units, to include five Army divisions, to accomplish every mission.

At that point in the war, Ramadi was considered by some to be the most dangerous city in Iraq[citation needed], and the battalion suffered high losses during the deployment.

1-503rd was targeted by daily small arms, RPG, and mortar attacks and experienced a significant number of vehicle-borne improvised explosive devices, also known as VBIEDS or car bombs.

According to an interview with Lieutenant Colonel James Raymer,[11] by 2006, insurgent activity was markedly lowered from the year that 1-503rd conducted operations in Ramadi.

2d BN (ABN) 503d IN deployed to Regional Command South demonstrating unparalleled bravery fighting anti-coalition forces in the bloodiest spring since the original invasion in 2001.

The ROCK fought the Taliban and Al Qaeda in the Provinces of Helmand, Zabul and Kandahar and excelled in all aspects of the deployment to include facilitating a peaceful parliamentary election process in the fall of 2005.

Upon completion of its year-long deployment to Iraq, 1-503rd did not return to Korea, but instead relocated to Fort Carson, Colorado, with the rest of the brigade.

On 26 October 2011, 2-503rd was awarded the Presidential Unit Citation for the soldiers' "extraordinary heroism in action against an armed enemy" from 5 June to 10 November 2007.

[15][16] Staff Sergeant Salvatore Giunta received the nation's highest award for valor after running through heavy enemy fire to rescue a badly wounded comrade during a deadly ambush on 25 October 2007, in the Korengal Valley.