Sylvester was born on the 10th of September, 1916 to Polish immigrants in St Clairsville, Ohio. He was the youngest son and went on to enlist in the US Army in July of 1941. He was with Company B, 15th Infantry Regiment, 3rd Infantry Division when they deployed to Europe and it was his actions in Italy on the 24th of May, 1944 that would earn him the Medal of Honor. The citation reads:

Near Cisterna di Littoria, Italy, he charged 200 yards over flat, coverless terrain to destroy an enemy machine gun nest during the second day of the offensive which broke through the German cordon of steel around the Anzio beachhead. Fully 30 yards in advance of his squad, he ran into withering enemy machine gun, machine-pistol and rifle fire. Three times he was struck by bullets and knocked to the ground, but each time he struggled to his feet to continue his relentless advance. With one shoulder deeply gashed and his right arm shattered, he continued to rush directly into the enemy fire concentration with his submachine gun wedged under his uninjured arm until within 15 yards of the enemy strong point, where he opened fire at deadly close range, killing 2 Germans and forcing the remaining 10 to surrender. He reorganized his men and, refusing to seek medical attention so badly needed, chose to lead the way toward another strong point 100 yards distant. Utterly disregarding the hail of bullets concentrated upon him, he had stormed ahead nearly three-fourths of the space between strong points when he was instantly killed by hostile enemy fire. Inspired by his example, his squad went on to overwhelm the enemy troops. By his supreme sacrifice, superb fighting courage, and heroic devotion to the attack, Sgt. Antolak was directly responsible for eliminating 20 Germans, capturing an enemy machine gun, and clearing the path for his company to advance.

Present that day was Audie L Murphy, who would also receive the Medal of Honor for his actions in another battle, and not only did he witness Sylvester's actions, he wrote about them in his book called To Hell and Back. When Sylvester's men had stormed the final enemy emplacement, they returned to him to find that he had died from his wounds. He posthumously received the Medal of Honor on the 19th of October, 1945 and not only would a Boulder Victory-class cargo ship get named in his honor and would President Bush talk about his actions in a Memorial Day speech in Italy in 1989, but in 2017, a section of Interstate 70 near his hometown of St Clairsville was renamed the Sgt Sylvester Antolak Highway. In November of 2018, a Netflix original show, called Medal of Honor, featured Sylvester's story in episode one. Sylvester Antolak was 27 when he died and he is buried in the Sicily-Rome American Cemetery and Memorial in Nettuno, Italy; Plot C, Row 12, Grave 13.