Dwight W. Stannard was born around 1835 in New York. He married Alma Simmons around 1858, and they had at least seven children: Charles, born around 1861; Bessie, born around 1865; Ettie, born around 1871; Cora, born around 1873; Hattie, born around 1876; Ezra, born around 1879; and Emma, born around 1882. By 1860, he was working as a farm laborer in Boonville, New York.
He enlisted in the Union army on September 23, 1861, and he mustered in as a private in Company A of the 97th New York Infantry seven days later. The regiment took part in the Second Battle of Manassas, the Battle of Antietam, the Battle of Fredericksburg, the Battle of Chancellorsville, the Battle of Gettysburg, and the Overland Campaign. He was wounded on May 5, 1864, in the Battle of the Wilderness, and again on June 13, 1864, at White Oak Swamp, Virginia. Surgeons amputated his right arm, and he mustered out on August 10, 1864.
He returned to Boonville after the war and resumed his work as a farmer. He applied for a federal pension in October 1864 and eventually secured one. He moved to Forestport, New York, in the 1880s. He died on April 20, 1916.