William W. Harvey was born on March 4, 1844, in St. Johnsbury, Vermont, to Orange and Martha Harvey. His father was a laborer. By 1860, Harvey was working as a farm laborer in St. Johnsbury. He began working as a painter in the early 1860s.
He enlisted in the Union army on November 2, 1863, and he mustered in as a private in Company H of the 1st Massachusetts Heavy Artillery on November 19, 1863. According to his service records, he was 5 feet, 6 ¼ inches tall, with brown hair and blue eyes. He knew his family would "feal very bad to hear that I enlistad," but he believed "it is the best thing that I can do." In December 1863, he assured his family that he "like[d] to soldire first rait." He mailed home his bounty money, telling his parents to "pay my dets and then you take the rest and use it for to pay for the houcs."
He was wounded on May 19, 1864, and he spent the next few months recovering. He was arrested as a deserter in the fall of 1864. Union officials transferred him to the 14th Company of the 2nd Battalion, Veteran Reserve Corps on March 18, 1865.
Harvey returned to St. Johnsbury after the war and resumed his work as a painter. He applied for a federal pension in October 1865 and eventually secured one. He married Elsie Knapp on July 5, 1870, and their daughter Elsie was born around 1873. They moved to Plainfield, New Hampshire, in the 1860s and then to Readfield, Maine, in the late 1800s. By 1900, he was working as a manufacturer in the wool industry. He died of “chronic valvular heart disease” on May 22, 1911, in Springfield, Massachusetts.