Ignatz Gresser was born on August 15, 1835 at Malach, Germany. He subsequently immigrated with his family to the United States as a young man about 1851. He was a shoemaker by trade. He was 26 years of age when the War Between the states was declared.

When the American Civil War broke out, he was a third corporal of the Allen Infantry, a militia unit under the command of Captain Thomas Yeagher that had been organized in 1859. Captain Thomas Yeagher mobilized the militia unit and the unit traveled to Harrisburg and was mustered in on April 18, 1865. This unit along with four other Pennsylvania militia units were the first to be transported to defend Washington, D.C. against attack by Confederate forces. These five companies and only these five became known as the "First Defenders". The average age of the men that made up the Allen Infantry was 26 years. The Allen Infantry was belatedly assigned to Company G' of the Twenty-fifth Pennsylvania Volunteer Infantry Regiment. The Allen Infantry militia men had enrolled for ninety days.

Yeagher's Allen Infantry was the first to arrive home in Allentown on July 24th, 1861. They were greeted with a parade, serenaded and dined by the local populace.

Ignatz Gresser resumed his occupation as shoemaker in Allentown, Pennsylvania. It was not until August 13, 1862, a little more than a year after his return from the original ninety-days service that he enrolled for nine months service with Company D' of the One Hundred Twenty-eighth Pennsylvania Volunteer Infantry Regiment. He was given the rank of Corporal. All of the recruits in Company D and Company G were from Lehigh County.

The One Hundred and Twenty-eighth Pennsylvania Volunteer Infantry Regiment arrived at Antietam at 2 a.m. on the morning of the 17th of September. Barely more than a month had passed since the regiment had been organized. At half past six in the morning, the regiment was ordered into the fight. They made a gallant charge through the wood and into the memorable corn-field, where the enemy lay concealed. The struggle was desperate and the regiment lost some of the bravest and best. The action in the cornfield was severe, thirty-four killed, eighty-five wounded, of whom six subsequently died of their wounds.

It was during this action at Antietam that Ignatz Gresser would distinguish himself. He subsequently reported that he had captured two Confederate infantrymen and was ordered to escort them back behind the lines and to turn them over to the cavalry. When Gresser exited the cornfield Corporal William Sowden, who had suffered a serious leg wound called out and asked Gresser if he could come and get him. Gresser replied that he would come back for him as soon as he placed the Rebels under guard. Gresser returned and found Sowden near the Rebel lines, bullets were flying all about. Sowden would likely have died on the field of battle had not Gresser helped him from the field. Gresser reports that he not only helped Sowden but another soldier as well.

On May 1, 1863 the regiment arrived at Chancellorsville and participated in the battle, suffering significant losses. The regiment was subsequently relieved from duty and was mustered out on May 19, 1863, having completed its term of service.

Ignatz Gresser must be considered the hero of Allentown and the greater Lehigh Valley area. But he was not immediately thought of in this manner. Ignatz Gresser was presented with the highest honor a military man can receive, the Medal of Honor, but the award did not come until 33 years after the event that earned it for him. It was December 12, 1895; Ignatz Gresser was 56 years of age, when the medal was awarded. Corporal William Sowden, although wounded at Antietam, recovered from his wounds and served his full term, being mustered out with the company on May 19, 1863. Sometime after the Civil War ended William Sowden became a United States Congressman and it was in his capacity as a Congressman that he was able to secure the coveted honor for his comrade. William Sowden died on March 3, 1907 and is buried in the Union and West End Cemetery.