William Dignan was born around 1842 in Norristown, Pennsylvania, to Charles and Eliza Dignan. His father was a “laboring man” who died on November 16, 1848. He grew up in Norristown and, according to his mother, “from the time he was able and old Enough to do so, [he] did aid and contribute towards her support.” By the early 1860s, he was earning $6 per week, which of which went to support his mother.
He enlisted in the Union army on September 20, 1861, and he mustered in as a private in Company D of the 51st Pennsylvania Infantry. The regiment took part in the Second Battle of Manassas, the Battle of Antietam, the Battle of Fredericksburg, the siege of Vicksburg, the Overland Campaign, and the siege of Petersburg. He eventually earned a promotion to sergeant. He died near Petersburg, Virginia, on June 18, 1864. According to one comrade, he “was struck by a ball in his forehead,” and he died two hours later.