All members of the regiment were parachute volunteers, but only a minor fraction were actually qualified jumpers during training at Camp Toccoa, GA. So, when that very arduous training was over in March 1943, the unit marched to Atlanta, GA, a distance of 105 miles (169 km). They then moved to Fort Benning, GA, to jump train all members not previously qualified.

With jump training over, the regiment was assigned to the Airborne Command at Camp MacKall, NC. This was its home base during prolonged maneuvers in North Carolina, Tennessee, and Louisiana, and until January 1944, when the regiment deployed to England, by way of Camp Myles Standish, MA. Once in England the 501st became a permanent attachment of the 101st Airborne Division and was a vital part of that famous unit for the duration of World War II.

In England, training was hard, realistic and became increasingly oriented toward an airborne assault into German-held Europe. Although none of the soldiers knew this initially, the regiment was training for Operation Overlord, the secret allied plan for the combined air, naval, amphibious, and airborne operations to breach AH's "Atlantic Wall." As D-Day drew closer, a few key commanders and staff were briefed on the part the 101st would play in Operation Overlord. Then with D-Day just days away, the 501st with the rest of the division was sequestered in well guarded marshaling camps where every man finally learned his own mission and the overall mission of the 501st and the 101st Airborne Division. These very extensive and intensive briefings were to later prove vital during actual operations.

The 501st (less 3rd Battalion) took off from Merryfield Airport at 2245, 5 June 1944, while the 3rd Battalion departed at the same time from Welford. All units flew across the English Channel and were set to drop into Normandy, five hours prior to the seaborne landing. The 501st drop zones were north and east of Carentan. Two battalions were to seize key canal locks at La Barquette and destroy bridges over the Douve River, while the third battalion was in division reserve.

The troop aircraft formations were widely scattered due to a combination of low clouds, poor visibility and enemy anti-aircraft fire. This caused highly scattered drops and units were widely dispersed across the battlefront. The ensuing action bore little resemblance to their briefing, but because the soldiers were well prepared, the regiment and the division accomplished its multiple missions, but none of them as rehearsed. The success was credited to the initiative, stamina, and daring of individual parachutists, who decided how best to accomplish some part of the overall mission. The capture of a key causeway from Utah Beach at Pouppeville by a scratch force of about 100 officers and men, formed around a nucleus from the 3rd Battalion (division reserve) of the 501st, was typical. Members of this ad hoc force included both General Maxwell Taylor and Assistant Division Commander Gerald Higgins. General Taylor later quipped that, "Never were so few led by so many."

Fierce fighting in Normandy by no means ended with D-Day, but continued with important results in assisting the amphibious landings and joining the beach at Utah to that at Omaha. The efforts of the 501st came at high cost: the regiment lost 898 men killed, wounded, missing, or captured.

The 501st returned to its base in England in mid-July, slowly regaining its pre-D-Day capabilities with many replacements and another round of intensive training. They received a presidential citation for their action in Normandy. They were briefed on several planned air assaults into France, each aborted when the allies overran planned objectives. In the early fall of 1944 they began preparing for an airborne assault into the occupied Netherlands.

Code-named "Market Garden," it combined a deep airborne thrust through the west of the Netherlands by the 1st Allied Airborne Army, with an overland drive by the British 2nd Army. The plan visualized airborne forces seizing key bridges over rivers and canals so 2nd Army could move very deep and fast over a distance of more than 100 miles (160 km), past the Rhine River, the last major water obstacle short of Berlin. This airborne assault would be made in daylight. The 101st Airborne Division was assigned the southernmost bridges at Eindhoven, Son, Sint Oedenrode and Veghel, with the 501st assigned the Veghel Bridges. The airborne assault went as scheduled on 17 September 1944, with an improved performance by troop carrier units. Most drop zones were hit with good drop patterns.

1st Battalion, 501st Parachute Infantry Regiment, however, was dropped some 5 miles (8.0 km) east of its planned drop zone. In spite of this, the four bridges in Veghel were captured intact. Then began the really difficult part of the operation, keeping open the highway over which 2nd Army must pass to reach the British 1st Airborne Division, which was fighting for its life at the northern end of the airborne corridor. The fatal flaw in the plan became more evident each day as the forces proved too few to both keep open the key highway and also fight on to a linkup with the British Airborne across the Rhine. The 1st Airborne Division paid the full price for this flaw as they went down fighting against overwhelming odds; less than two thousand men escaped death or capture.

The 501st, with the rest of the division, moved from initial objective areas to positions on "the island" between the Waal and Rhine Rivers; it became clear that they would not be withdrawn from the Netherlands after a few days, as they had been told; their combat skills were too much needed by the British. The prolonged fighting on "the island" was anything but the way to use an airborne unit. After the initial hard fighting it became a static war of patrolling and attrition, principally by artillery and mortars. One such mortar attack, near Heteren, on 8 October 1944, fatally wounded Colonel Johnson.

Colonel Johnson was the best-known loss, but with him they lost 661 other fine soldiers. LTC Julian Ewell, a taciturn West Pointer, succeeded COL Johnson. Much less an extrovert than Johnson, he more than made up for any lack of "flash and dash" with a keen mind, tactical prescience and all around professional competence.

After 72 days of combat in the Netherlands the division returned to a new staging area in Mourmelon, France, for what everyone thought would be a long, well-deserved rest. Accordingly, many men were on leave or pass, the Division Commander was in the United States, the Assistant Division Commander was in England (leaving the Artillery Commander, General McAuliffe, in command), and there still were major shortages of equipment and supplies that had not been replaced after the Netherlands.

The division was ill-prepared for the word they received in the late evening of 17 December. The Germans had launched a major offensive at dawn on 16 December through the Ardennes in the lightly held sector of VII Corps. At that time SHAEF's Reserve consisted of the 101st and the 82nd. The 101st was ordered to move "truckborne" to Bastogne, the hub town of a major radial road net, to stem the oncoming Germans. General McAuliffe ordered the move by regimental combat teams without waiting for any absentees. The 501st was the lead combat team in the division move, and after a grueling truck ride, reached Bastogne at about 2230 hrs.[4] Thus, by midnight, the 501st was the only regiment combat team ready for action. Ewell asked McAuliffe for a definite assignment and was ordered to move out on the eastern road through Longvilly and seize and hold a key road junction beyond Longvilly. The 501st was the first to fight at Bastogne when one of its battalions ran into the enemy near Neffe, a few kilometers out of Bastogne.

Thus began the defense of Bastogne in which the 501st gave up not one foot of ground, and in which the division, and its comrades in arms, stopped cold everything the Germans could throw at them, ruined AH's offensive time table and eventually won the 101st the first presidential unit citation ever awarded to a full division.

Once again, the 501st paid a dear price of 580 killed, wounded or captured. One casualty was Colonel Ewell, who was badly wounded and relinquished command to LTC Robert Ballard, who had commanded 2nd Battalion from the beginning. Bob Ballard was a quiet Floridian who was not a professional soldier like Johnson or Ewell, but a fine officer who had learned how to command quietly and effectively while winning the admiration and respect of his men. Ballard continued in command of the 501st until the end of World War II. Operations after Bastogne would have been anticlimactic under most any circumstances, except for the light skirmishing in Alsace, and the drive into Germany's last redoubt, Bavaria, truly seemed like a cakewalk. The living in Germany after V-Day was good indeed, but rudely interrupted by orders to move back to billets in Joigny and Auxerre, France. Troops were advised not to take any captured cars or loot with them.

Once in France the 501st began training for an invasion of Japan. On 20 August 1945, the 501st was disbanded, ahead of the inactivation of the 101st Division in November 1945.