William H. Parshall was born on February 25, 1845, in Lebanon, Ohio, to William F. Parshall and Henrietta Dey. His father was a banker who owned $10,000 of real estate and $25,000 of personal property in 1860. Parshall grew up and attended school in Lebanon. He enlisted in the Union army on May 29, 1862, and mustered in as a private in Company B of the 73rd Ohio Infantry. He mustered out on September 20, 1862. He returned to the Union army a year later, serving in the 4th Ohio Infantry from August 1, 1863, until February 15, 1864. He enlisted for a third time on March 25, 1864, mustering into the 79th Ohio Infantry. He mustered out on July 26, 1865.
Parshall and his parents moved to Walker, West Virginia, after the war. Parshall worked as a merchant, and by 1870, he owned $1,000 of personal property. He married Harriet Davis in Brooklyn on February 25, 1881, and they had three children, two of whom survived: Henrietta, born in October 1882; and Dora, born in March 1900. Parshall worked as an office clerk, and the family rented their home in Brooklyn. Harriet died on June 17, 1901. Parshall lived with his daughters in Brooklyn until his death from “Chronic Nephritis” on August 26, 1911.