Gilbert Keenholts was born around 1827 in Albany, New York. He married a woman named Matilda sometime before 1850, and they had at least two children: James, born around 1856; and Emma, born around 1860. They lived in Guilderland, New York, and Keenholts worked as a farmer, day laborer, and painter. By 1860, he owned $100 of personal property. He enlisted in the Union army on July 30, 1862, and he mustered in as a private in Company D of the 7th New York Heavy Artillery on August 18. According to his service records, he was 5 feet, 6 inches tall, with dark hair and blue eyes.
He supported Abraham Lincoln in the election of 1864, praying that votes would “elect Olde Aabe by a Large Majority in spite of McClellan and all the Northern copperheads.” If soldiers were “allowed to vote,” he insisted, then Lincoln would “shurley [be] elected again for you can take us all through and there will be 7 out of 10 that says he ought to keap his seat untill this war is setled.” He was wounded in the right shoulder in the Battle of Spotsylvania Court House on May 19, 1864, and Union officials sent him to Washington, D.C., to recover. He died there of “exhaustion from chronic diarrhoea [sic]” on September 23, 1864.