Born in New York, he graduated from the U. S. Military Academy at West Point on July 1, 1846 whereupon he received a brevet to 2nd Lieutenant, 7th Infantry. With the outbreak of the Mexican War he was promoted to 2nd Lieutenant and assigned to the 4th Infantry. He was at the Siege of Vera Cruz, March 9-21, 1847; the Battle at Molina del Rey, September 8, 1847; and the Assault and Capture of Mexico City. For gallant and meritorious conduct in the Battle of Molina del Rey he was breveted to 1st Lieutenant on September 8, 1847.

He was promoted to 1st Lieutenant on January 1, 1848 and assigned in garrison at East Pascagoula, MS in 1848 and Detroit, Mich. from 1848-1850. From 1850-1852 he was on recruiting duty following which he was assigned frontier duty at Benicia, CA, Ft. Vancouver, WA and Ft. Steilacoom, WA through 1855. He was promoted to Captain, 4th Infantry, July 31, 1854. He continued on frontier duty in California and Oregon until arriving at Ft. Hoskins, OR in 1861.

He was promoted to Major, 11th Infantry, May 31, 1861. He commanded the 11th Infantry (Army of the Potomac) in the Virginia Peninsular Campaign, March to August, 1862, being engaged in the Siege of Yorktown, Battle of Gaines's Mill and Battle of Malvern Hill. He was breveted to Lieutenant Colonel on July 4, 1862 for gallant and meritorious service during the Peninsular Campaign. He served in the Northern Virginia Campaign, August to September, 1862, including the Battle of Manassas; in the Maryland Campaign, commanding Regiment engaged in the Battle of Antietam and the Skirmish at Sharpsburg. He also served in the Rappahannock Campaign, commanding Regiment March to June, 1863, engaged in the Battle of Chancellorsville; in the Pennsylvania Campaign (Army of the Potomac), being engaged in the Battle of Gettysburg. He was breveted to Colonel, July 2, 1863 for gallant and meritorious service at Gettysburg.

Floyd-Jones was in command of Ft. Independence, MA, August 15 to October 28, 1863 and of the Fortifications of Boston harbor, October 28, 1863 to March 6, 1865. He was at Detroit, MI from March 31 to August, 1865. Following the Civil War, Floyd-Jones served in command of Newport Barracks, KY, October 12, 1865 to March 13, 1866 and of Little Rock, AK, March 27 to August 29, 1866. Following sick leave he was assigned as Acting Assistant Inspector-General and Judge Advocate of the Department of Arkansas, December 1, 1866 to February 13, 1867; in command of a regiment and Ft. Smith, AK, to October, 1867; and of Ft. Gibson and District of Indian Territory, October 24, 1867 to January 20, 1868. On June 25, 1867 he was promoted to Colonel.

Following a leave of absence, Floyd-Jones was in command of a regiment and Ft. Gibson, Indian Territory, February to April, 1869. He served as Superintendent of Indian Affairs in Idaho Territory, from June, 1869 to November 1, 1870. From February 15, 1871 to January, 1872 he commanded Ft. Dodge, KS, followed by commands at Ft. Hays, KS; Ft. Riley, KS; Holy Springs, MS; Jackson Barracks, LA; and Helena, MT. He retired March 20, 1879.