John Cotlett Garrett Key, lawyer and Confederate officer, was born in Edgefield District, South Carolina, in 1809. He was the son of John Alford Key and Winifred (Simpkins) Key. Key studied law and practiced in Sparta and Belview, Louisiana. He married Ann Ardis of Louisiana. He moved to Texas, probably after the death of his wife, and settled in Gonzales County, where he resumed his practice. In 1858 he married Martha B. Hamon. They had three children.
At the beginning of the Civil War, Key organized a company of infantry, the "Hardeman Rifles," in Gonzales County for service in the Confederate Army. This unit trained in Van Dorn before embarking on the steamer The Florida at Beaumont to Virginia in the summer of 1861 to be incorporated into the Fourth Texas Infantry Regiment as Company A. Key himself joined the Fourth Infantry as a captain. On March 3, 1862, Key was promoted to major and spent the remainder of the spring in Texas as a recruiter. In early summer, he rejoined his unit and on June 27 was wounded at the battle of Gaines' Mill. Following this action, on July 10, 1862, Key received promotion to colonel. At the battle of Gettysburg, on July 2, 1863, Key was serving as commander of the Fourth Infantry when he was wounded again. This injury was serious enough to require several weeks of convalescence. He returned to his unit in the autumn of 1863 but suffered lingering effects from his injuries. Key resigned his commission on April 29, 1864, and returned to Gonzales County. He died in 1866 in Gonzales, Texas, and was buried in the Masonic Cemetery there.