Sam William was inducted at Camp Shelby, Mississippi, and left for basic training at Fort D.A. Russell in Marfa, Texas, on
October 17, 1942. Having just celebrated his twenty-first birthday on August 1, 1942, he embarked on a journey he would never forget.

Most of the men in the 81st Chemical Mortar Battalion, which was formed on April 25, 1942, were from the South. Their training in the United States continued at Camp Polk, Louisiana on April 5, 1943. One month later, they traveled to Camp Gordon Johnson in Carrabelle, Florida. After amphibious, commando and physical training, on June 12, 1943, the battalion arrived at Camp Pickett, Virginia. In Virginia the men were trained in the use of the Springfield rifle, the carbine and the BAR. Three months later, they were off to the staging area at Camp Shanks, New York. On October 20, 1943, the battalion embarked on the Capetown Castle, and by November 2, 1943, the men arrived in Liverpool, England. Sam would remain in the European Theater for twenty-three months.

From the winter of 1943 until the spring of 1944, the 81st Chemical Battalion trained in Penkridge, Staffordshire, in the Midlands country of England. In March, they traveled to Poole, Dorset. In April the battalion was attached to the 1st Infantry Division. By May, the men were alerted that they would participate in one of the greatest events of history, the invasion of Europe. Just before dawn on June 6, 1944, the armada of ships carrying the various companies approached the coast of Normandy. On D-Day, Sam William landed on the section of Normandy Beach that had been given the code-name Omaha. Since they were the first to arrive, enemy fire was inflicting heavy casualties. The men remained under heavy fire on the beach until late in the afternoon.

During the fifteen months that followed, Sam drove ammunition trucks filled with white-phosphorus and high explosives. He participated in The Battle of the Hedgerows, which lasted from June 14 to July 26, 1944. His battalion then went to St. Lo and the Battle of Hill 192. Next, they marched to Paris and on to the Siegfried Line.

On October 19, 1944, as the men slept in Jarny, France, an ammunition truck was hit by an explosive from a German air attack. Without regard for his personal safety, he ran barefoot from his sleeping quarters to the truck and drove it a safe distance from his fellow soldiers. For this act of bravery, he received the Bronze Star.

His citation read:

Technician Fifth Grade Sam W. Gross, 34427380, Chemical Battalion, for heroic service in connection with military operations against the enemy in France on 19 October 1944. In the course of an intense German artillery barrage in the dead of night near Jarny, France, a heavy shell exploded near two parked ammunition trucks, one of which was packed with high explosive munitions. Shell fragments cut into the loaded truck and split two large mortar shells, set on fire a stack of explosives on the ground, and scattered burning white phosphorous over a 100-yard radius. The empty truck burned fast and threatened the other vehicle. Voluntarily, and with complete disregard for his personal safety, Technician Fifth Grade Gross leaped into the burning truck, drove it over the phosphorous strewn area, stopped, and then extinguished it. When this fire was out, he returned to help clear the rest of the seared area. Technician Fifth Grade Gross' initiative, courage and outstanding devotion to duty reflect distinct credit upon himself and the Army of the United States. Entered Military Service from Mississippi.

While taking and holding the Saar Valley, the men endured the Battle of the Bulge. This battle, which lasted from December 16, 1944, to January 28, 1945, was the largest land battle of World War II in which the United States participated. More than a million men fought in this battle, including some 600,000 Germans, 500,000 Americans, and 55,000 British. With little rest, the men concentrated on the Saar-Moselle Triangle. They crossed the Rhine on March 27, 1945.

The 81st Chemical Battalion received a Presidential Citation for their extraordinary heroism and outstanding performance of duty in action. They received 5 battle stars for their support in the following major battles of World War II:

D-Day Invasion, Battle of the Hedgerows, Hill 192, Seigfried Line and The Battle of the Bulge.

Sam William Gross separated from the United States Army on September 8, 1945, almost three years after his induction. He was honorably discharged from service with the highly decorated 81st Chemical Mortar Battalion.

This article appeared in The Carthaginian shortly afterward:

After futile efforts to contact each other on battlefields of England, France, Germany and Belgium, it was on home soil, over a delicious luncheon in the home of Mr. And Mrs. W. L. Gross that their son, Sam William, who received his honorable discharge while en route home, and a relative, S/Sgt. William C. Dickens, finally exchanged their stories of much hard and continuous fighting until peace was won. The lines of ribbons, the bronze and battle stars and the medals of honor that bedeck these life long neighbor boys' uniforms, and the various citations that were bestowed upon them while in battle is conclusive proof it is well earned rest they are enjoying.