Loomis T. Palmer was born around 1844 in Connecticut to Elliot and Florilla Palmer. His father was a Congregationalist minister who owned $3,500 of real estate and $1,300 of personal property by 1860. The family lived in Stafford, Connecticut, until the 1850s, when they moved to Newark, New Jersey.
He enlisted in the Union army on Jun 11, 1861, and he mustered in as a private in Company C of the 67th New York Infantry on June 24. The regiment took part in the Seven Days’ Battles, the Battle of Gettysburg, the Overland Campaign, and the siege of Petersburg. He expressed devotion to the Union. In October 1863, he assured his parents that "your son...will do his duty & God helping him will never show himself a coward. sooner let me fall, than to show myself weak and backward in sustaining our cause." He asked them to "remember him as one who fought for his country."
He was promoted to corporal on May 30, 1864. On September 1, 1864, Union officials transferred him to Company C of the 65th New York Infantry. The regiment took part in the siege of Petersburg and the Appomattox campaign. He supported President Abraham Lincoln in the election of 1864. In September 1864, he declared that the "day has now come when we as a nation can show ourselves--give Gen Grant reinforcements. Abe our hearty support, carry forward this draft & we may hope for Peace ere the New Year." He mustered out on July 17, 1865.
He returned to New Jersey after the war, and he married Maria Vannostrand on May 8, 1866. They lived in Elizabeth, New Jersey, and Palmer worked as a bank agent. By 1870, he owned $1,000 of personal property. He died on May 24, 1896, in Portland, Connecticut.