William Selby Harney, United States Army officer, was born in Haysboro, near Nashville, Tennessee, on August 22, 1800, the son of Thomas and Margaret (Hudson) Harney. After preparing for a career in the navy, he was commissioned a second lieutenant in the First United States Infantry on February 13, 1818. He displayed great prowess against the Creeks and Seminoles and was promoted to first lieutenant on January 7, 1819. After being transferred to the First Artillery on November 16, 1821, he returned to the First Infantry on December 21, 1822, and was promoted to captain on May 14, 1825. In 1833 he married Mary Mullanphy, daughter of a wealthy St. Louis plantation owner; the couple had three children. Harney was made a major in the paymaster corps on May 1, 1833, and lieutenant colonel of the Second Dragoons on August 15, 1836. He was brevetted to colonel on December 7, 1840, for "gallant and meritorious conduct" against the Seminoles in Florida. He was promoted to colonel of the Second Dragoons, then stationed at San Antonio, on June 30, 1846. On September 23, with the coming of the Mexican War, Harney led his regiment out of San Antonio as the vanguard of Brig. Gen. John Ellis Wool's campaign against Chihuahua. After fighting in the battle of Buena Vista under Maj. Gen. Zachary Taylor, he was transferred to the command of Maj. Gen. Winfield Scott and took part in the amphibious landing below Veracruz as Scott's senior cavalry officer. Harney and Scott were never on friendly terms, and Scott, mistrusting Harney's judgment, relieved him of command. Harney, however, refused to be removed and appealed to his superiors in Washington, President James K. Polk and Secretary of War William Learned Marcy, who reinstated Harney over Scott's objections. Despite this unpleasantness, Harney fought brilliantly and was brevetted to brigadier general on April 18, 1847, for his role in the battle of Cerro Gordo on April 12, 1847. He continued with Scott's command throughout the campaign that culminated in the capture of Mexico City on September 13, 1847, and received the substantive rank of brigadier general on June 14, 1858.
On May 14, 1849, on the death of Col. William J. Worth, Harney assumed command of Military Department Number Five, which comprised almost all of the settled portion of Texas. He was replaced on July 7, 1849, by Col. George M. Brooke, but returned to command on March 9, 1851, when Brooke died. Col. Persifor F. Smith replaced Harney on September 16, 1851, but Harney returned to command of the department for the final time on December 3, 1852. He established his headquarters first at Austin and then at Corpus Christi and was again relieved by Smith on May 11, 1853. In 1854 he was reassigned to the north plains, where he won the decisive battle of Blue Water in 1855, forcing a peace on the Sioux Indians. He was rewarded in 1858 with the command of the Department of Oregon but was recalled on July 5, 1860, due to his militant anti-British attitude.
At the outbreak of the Civil War Harney was commander of the Department of the West, with headquarters in St. Louis, and was one of only four generals in the regular United States Army. Although a Southerner in sympathy and married into a wealthy slaveowning Missouri family, Harney remained with the United States Army in 1861. His Confederate attachments rendered him something of an embarrassment to Union authorities in the trans-Mississippi theater, however, and he was relieved of his command on May 29. He retired from active duty on August 1, 1863, but received a final brevet, to major general, on March 13, 1865, "for long and faithful service." Appointed to an Indian peace commission by Andrew Johnson in 1865, Harney was instrumental in the negotiation of the important Medicine Lodge Treaty of 1867. Thereafter he lived in retirement at Pass Christian, Mississippi, and in St. Louis. After being divorced from his first wife, late in life he married his nurse, a Mrs. St. Cyr. He died on May 9, 1889, at Orlando, Florida, and was buried at Arlington National Cemetery. Camp Harney in Zapata County was named in his honor.