William Rollin Pelton was born on May 7, 1841, in Sherman, New York, to William and Ermena Pelton. His father was a farmer who owned $3,600 of real estate and $800 of personal property by 1860. He grew up and attended school in Mina, New York, and by 1860, he was working as a farmer. He enlisted in the Union army on August 19, 1862, and he mustered in as a private in Company D of the 112th New York Infantry on September 1. The regiment took part in the Siege of Suffolk. Pelton was transferred to the United States Signal Corps on July 20, 1863, and he mustered out on June 24, 1865.
Pelton returned to his mother’s household in Sherman after the war. By 1870, he was working as a fire and life insurance agent, and he owned $300 of personal property. He married Eudora Newell in the early 1870s, and their daughter Camilla was born around 1879. By 1880, they were living in Chautauqua, New York. He died in Syracuse, New York, on November 5, 1892.