William J. Murphy was born around 1832 in Ireland. His family immigrated to America around 1837, and he eventually settled in Danbury, Connecticut. He married a woman named Eugenia around 1854, and they had at least three children: Charles, born around 1855; Mary, born around 1859; and Imogene, born around 1861. He worked as a hatter, and by 1860, he owned $3,000 of real estate and $200 of personal property.
He enlisted in the Union army on April 19, 1861, and he mustered in as a private in Company E of the 1st Connecticut Infantry three days later. The regiment took part in the First Battle of Manassas. He mustered out on July 31, 1861.
He returned to Danbury after leaving the army, and he resumed his work as a hatter. By 1870, he owned $5,000 of real estate and $500 of personal property. He applied for a federal pension in June 1887 and eventually received one. He died on January 11, 1898.