Charles A. Gillett was born on March 24, 1841, near Shortsville, New York, to James McBurnet Gillett and Eliza Berry. His father was a farmer who owned $6,000 of real estate and $1,300 of personal property by 1860. Gillett grew up and attended school in Hopewell, New York.
He enlisted in the Union army on August 29, 1862, and he mustered in as a corporal in Company K of the 148th New York Infantry on September 5. According to his service records, he was 5 feet, 10 inches tall, with dark hair and blue eyes. The regiment took part in the Battle of Cold Harbor. In January 1863, he wrote that he “would like to enjoy peace at once and always. But war is as noble as a dangerous peace. I say dangerous because I am concern[ed] of such a peace.” He remained devoted to the Union cause. In February 1865, he celebrated the soldiers like himself, who "have been faithful in the discharge of duty and have risked their lives in our sacred cause." He was promoted to sergeant on August 27, 1864. He was wounded on October 2, 1864, but he eventually recovered and rejoined the regiment. He mustered out on May 3, 1865.
He returned to Hopewell after the war, and he married Mary Wakefield around 1872. They had at least seven children: Frances, born around 1873; Mary, born around 1874; John, born around 1876; Lewis, born around 1878; Fanny, born around 1880; Grace, born around 1882; and James, born around 1884. He worked as a farmer. He applied for a federal pension in December 1876 and eventually secured one.
They moved to Phelps, New York, in the late 1800s. He supported the Republican Party, and he served as secretary of his regiment’s veteran organization. He died in Kingston, New York, on February 24, 1917.