Gilbert Molleson Elliott was born in Thompson, Connecticut, on October 7, 1840, to Jason and Ruth Elliott. His father was a clerk and shoemaker who owned $4,000 of personal property by 1860. The family moved to Brooklyn, New York, in the 1840s, and Elliott attended the New York City Free Academy. According to one early biographer, he “received the gold medal for excellence as the leader of his class at four successive commencements, and [he] delivered the valedictory oration at his graduation in 1861.”
After Confederate forces attacked Fort Sumter in April 1861, Elliott reportedly “unfurled the stars and stripes from the college building, and in his address declared he would defend his country’s honor with his life’s blood.” He had planned to study law after graduation, but he abandoned those plans to enlist in the Union army.
He received a commission as a 1st lieutenant in Company E of the 102nd New York Infantry on October 3, 1861. The regiment took part in the Battle of Antietam, the Battle of Chancellorsville, the Battle of Antietam, and the Chattanooga campaign. He was promoted to captain on October 5, 1862, and then to major on March 18, 1863. He was mortally wounded in the abdomen during the Battle of Lookout Mountain on November 24, 1863, and he died later that day.