Born into a historically notable family on July 21, 1844 in New York City, Louis Hamilton was raised on Long Island and in Poughkeepsie, New York. His father, Judge Phillip Hamilton, was the son of Alexander Hamilton, a founding father of the United States and member of President George Washington's cabinet. Louis Hamilton was named after his grandfather, Senator Louis McLane, who also served as Secretary of the Treasury and Secretary of State in President Andrew Jackson's cabinet.
In September 1862, at the age of eighteen and with the assistance from influential friends, Hamilton was commissioned as a second lieutenant in the 3rd U.S. Infantry. He commanded a company at Fredericksburg, won brevets at Chancellorsville and Gettysburg, and fought at Petersburg and Appomattox. He was promoted to first lieutenant in May 1864.
In July 1866, Hamilton became the youngest captain in the Regular Army when he joined the 7th U.S. Cavalry and was assigned to command Fort Lyon, Colorado. He was an able and ambitious troop commander who was well liked by his fellow officers. His leadership skills under fire were admirably displayed on June 24, 1867, during the General Winfield Hancock's expedition. While in command of a small detachment, Captain Hamilton averted an Indian ambush and repulsed forty-five attacking Sioux near forks of the Republican River while pursuing Sioux under Pawnee Killer. He later commanded a detachment that followed Lieutenant Colonel George A. Custer east during the incident that led to Custer's court-martial.
Captain Hamilton's ambition, however, led to his death at the Battle of the Washita on November 27, 1868. Hamilton, who was assigned officer of the day and riding on Custer's left, was heard calling to his men to "keep cool, fire low, and not too rapidly." Hamilton was commanding a squadron on the initial charge into Chief Black Kettle's village when killed instantly by a bullet through the heart. Dr. Henry Lippincott, Assistant Surgeon, noted that the "ball entered about five inches below the left nipple, and emerged near inferior angle of right scapula. Death was instantaneous." Louis McLane Hamilton was buried with full military honors near Camp Supply, and later reinterred at Poughkeepsie, New York.
Greene, Jerome A. Washita: The U.S. Army and the Southern Cheyennes, 1867-1869.
Norman: University of Oklahoma Press, 2004. (pgs 63, 90, 101, 113-117, 121, 125, 134, 203, 251, 253)
Hardoff, Richard. Washita memories: eyewitness views of Custer's attack on Black Kettle's village.
Norman: University of Oklahoma Press, 2008. (pgs 15, 122-23, 162, 218, 243, 376)