Constituted 14 March 1941 in the Army of the United States as Company A, 502d Parachute Battalion Activated 1 July 1941 at Fort Benning, Georgia. Constituted 24 February 1942 in the Army of the United States as the 502d Parachute Infantry Regiment (less 1st Battalion). Was activated 2 March 1942 at Fort Benning, Georgia and was assigned 15 August 1942 to the 101st Airborne Division. The 502 was Inactivated 30 November 1945 in France.

The 502nd Infantry Regiment originated in July 1941, as the 502nd Parachute Battalion, an experimental unit formed to test the doctrine and tactics of parachute assault. On 2 March 1942, the unit was redesignated as the 502nd Parachute Infantry Regiment. The 1st Battalion, 502nd Infantry Regiment was activated on 1 July 1941, at Fort Benning, Georgia, and joined the 101st Airborne Division in August 1942.

Radio call sign: "KICKOFF" The 502nd Parachute Infantry under Colonel George Van Horn Moseley was activated as a battalion in 1941. The troops had already undergone significant training when the 101st Division was activated in mid 1942. The 502 or “five-oh-deuce”, as they became known, were increased in size to a regiment, and made the original TO&E Parachute Infantry Regiment in the 101st Airborne Division. Unlike other early Parachute Battalions, the 502 retained the same unit number and personnel when increased in size. To them for artillery support, was attached the only Parachute Field Artillery (PFA) battalion of the division, the 377th PFA Bn. The 321st was assigned to support the 506th and later, the 501 received support from the 907th,( both Glider Field Artillery battalions.) When the 101st settled in at Ft Bragg, N.C., the 502 made many practice jumps, becoming familiar with Maxton & Pope fields, and participating in war games near Evansville, Indiana. The Deuce sailed to England in September, 1943, with most of the divisional sub units. This ill-fated voyage aboard the SS Strathnaver was soon aborted, with the ship setting in to port at Newfoundland. There was salt water in the ship's fresh water tanks. On attempting to set sail once again, the Strathnaver struck rocks in the harbor and went to port again. Finally, another ship was arranged, the SS John Erickson, which transported Moseley's regiment the rest of the way to England. The total trip required six weeks. Meanwhile the 506th and much of the 327th GIR had already reached England on another transport.

The 502 settled in around the Chilton-Foliat and Hungerford areas, living in a combination of Nissen huts, tents, and English houses. After seemingly unending training in the cold, bleak English countryside, the Deuce finally received its orders for the D-Day Invasion. Flying in the first serials to depart from Membury and Greenham Common, the Deuce was primarily responsible for securing the two northerly exits (each of them causeways across swampy ground), behind Utah Beach. These were exits #4 (St Martin de Varreville), and #3 (Audoville la Hubert). Southwest of St Martin was a field containing four concrete blockhouses with German artillery pieces sited on the shoreline near Exit #4. Taking this position became the prime concern of the 502 regiment, which was to be aided by the 377th PFA Bn. On 6 June 1944, the Deuce had landed by parachute in France and discovered their primary objective had already been neutralized by air bombardment. Roadblocks were established to halt enemy traffic along Exit #4, and a makeshift force under LTC Robert Cole, the 3rd Bn C.O., took Exit #3. The regimental C.O., Colonel Moseley sustained a badly broken leg and would soon be forced to relinquish command. The planned regimental C.P. at Loutres was discarded and a new one at Objective 'W' at St Martin de Varreville, was opened by Moseley's successor, the erstwhile EXO, Mike Michaelis. As the men of the Deuce assembled, the groups headed past Division HQ at Hiesville and reformed at la Croix Pan and Blosville, along the N-13, north of St Come du Mont. They migrated south and received their toughest mission of the war: to spearhead the drive south along the N13 Carentan Causeway. This attack, staged on 10-11 June, 1944 caused so many friendly losses that the 502 men dubbed the Carentan Causeway "Purple Heart Lane". Day and night, the Deuce, with 2nd Bn in reserve, fought along the single, elevated road, doggedly advancing even as they were picked off like clay pigeons by Germans firing from the swamps on either side of the road. After crossing the Madeleine River Bridge, known as Bridge #4, LTC Cole ordered all present to fix bayonets and charge the Ingouf farm. For leading this successful charge, Colonel Cole was later awarded the Congressional Medal of Honor. All day fighting raged on 11 June, near the Ingouf farm and south of it, in a cabbage patch, where 1st battalion troops fought the 3rd Bn of the German 6th Parachute Regiment. The Germans were finally swept away and Cole's surviving men went into reserve. The 2nd battalion came up on 13 June to aid the 506th near Bloody Gulch SW of Carentan. After pulling security duties near Cherbourg in late June, the 502 sailed back to England on LSTs in July, to await another mission.

On 17 September, 1944, the 502 landed by parachute on the Zon, Holland DZ. Second Bn was in reserve near Wolfswinkel at first. First Bn went north to capture and outpost St Oedenrode. Third Bn sent patrols through the Zonsche forest, probing toward the town and bridge at Best. German troops denied U.S. forces the bridge at Best by blowing it up. In fierce fighting just short of the bridge, Pfc Joe Mann was killed when he lay on a German grenade to save comrades who were in the same pit with him. Pfc Mann received the second and only other CMH (both awarded posthumously), in the WW2 101st division. Germans of the 15th Army, migrating east toward the German border, were thrown into the fighting near Best in increasing numbers. LTC Cole was fatally wounded by a sniper in the Zonsche Forest. Second battalion was committed to the fighting there. With help from British armor, the Deuce, minus 1st Bn, turned the tide and captured many hundreds of German troops near the Zonsche Forest. The Third Bn EXO, Major John P. Stopka assumed command of Cole's Battalion. On 22 September, LTC Michaelis was WIA by an artillery shell and command of the 502 passed to erstwhile 2nd Bn commander, Steve Chappuis. When the 101st migrated north to hold positions on the 'Island', SW of Arnhem, the 502 was in reserve near Dodewaard, where action was limited to patrolling. Some losses were sustained there, mainly from landmines such as the German mercury tilt and Riegle mines.

After a brief rest period at Camp Mourmelon le Grand, France, the 502 rushed north in trucks with the rest of the 101st to hold the crucial road and rail junction of Bastogne Belgium. Surrounded there, the 502 held positions on the north and northwest portion of the circle. Enemy probes began hitting them after failing elsewhere in the circular defense line. A Christmas morning fight at Champs, Belgium, followed by repulse of an armored attack on the C.P. at Rolle, were memorable events. On 3 January, 1945, a heavy engagement took place above Longchamps, Belgium involving 2nd Battalion of the Deuce. The 19th SS Panzer Grenadier Regiment of the Hohenstauffen division was able to capture almost forty American parachutists there, mostly members of F/502. The following week saw bloody fighting along the railroad line running NE through the Bois Jacques forest. During this drive, LTC John Stopka was KIA, and Cecil Simmons became the third and final commander of 3/502. The objective, Bourcy, Belgium, was finally taken. (The railroad line mentioned no longer exists-it was salvaged for steel in 1995-96).

After Bastogne, the Deuce traveled to the 7th Army (Alsace) front with the rest of the 101st Airborne in mid January. After holding a line along the Moder River for over a month, they took boxcars to Mourmelon le Petit, France. April 1945 saw the Deuce in the vicinity of Dusseldorf, helping to close the Ruhr Pocket along the Rhine River. In May, the Deuce arrived at Berchtesgaden a bit later than the 506th, 327th and 321st, who led the division advance into the Obersalzberg area.

Members of the Deuce with high points sailed home in the summer of 1945, while others, awaiting discharge were absorbed into the Deuce in the interim. Returning to France, this time the Joigny-Auxerre area, the Deuce made one final 'pay jump' in September, 1945. The regiment and the division were deactivated in December 1945. The unit would be resurrected with the 101st Airborne in 1956.