John Curtis Gilmore was born on April 18, 1837 in Canada. Later that year his parents moved across the border to Louisville, New York. He graduated from the Albany, New York, Law School and was living in Potsdam, New York at the start of the war.
On May 15, 1861, he became captain of Company F of the 16th New York Infantry. He was brevetted major on September 29, 1862 for “gallant and meritorious service” at Antietam and lieutenant colonel for “gallant and meritorious service” at Fredericksburg.
He earned the Medal of Honor on May 3, 1863, at the Battle of Salem Heights, Virginia during the Chancellorsville Campaign. According to the citation he “Seized the colors of his regiment and gallantly rallied his men under a very severe fire.” He received the medal on October 10, 1892.
Gilmore mustered out at the expiration of his term on May 22, 1863. In March of 1865 he was appointed lieutenant colonel of the 193rd New York Infantry, and mustered out with his regiment in January of 1866.
Gilmore was commissioned 2nd lieutenant in the 12th United States Infantry Regiment in May of 1866. He transferred to the 30th Infantry in 1866, was promoted to captain in the 38th Infantry in January of 1867, and transferred to the 24th Infantry in 1869. In August of 1890 he was promoted to major and assigned to the staff of the Adjutant General. He was promoted to lieutenant colonel in November of 1896.
In the Spanish-American War he served in Cuba and Puerto Rico as Chief of Staff to General Nelson A. Miles as Brigadier General of Volunteers. In April of 1900 he was promoted to colonel in the United States Army.
Gilmore retired in April of 1901. He died in Washington, D.C. on December 22, 1922 and is buried in Arlington National Cemetery next to his wife, Harriet Louise Gilmore, and his son, Colonel John Curtis Gilmore, Jr..