Hugh Kilpatrick was born in New Jersey in 1836. On the outbreak of the American Civil War he joined the Union Army and was commissioned captain of the 5th New York regiment. He was wounded at Big Bethel (10th June, 1861) but recovered to be promoted to colonel of the 2nd New York Cavalry in September, 1861.

Kilpatrick took part in the defence of Washington before fighting at the second battle of Bull Run (August, 1862). He joined General George Stoneman attempt to capture Richmond (June, 1863). Kilpatrick developed a reputation for "dare-devil recklessness that dismayed his opponents and imparted his own daring to his men."

He also fought at Gettysburg (July, 1863) before joining William T. Sherman who claimed: "I know Kilpatrick is a hell of a damned fool, but I want just that sort of man to command my cavalry." He led the cavalry corps of the Army of the Cumberland during the Atlanta Campaign. Promoted to major general, Kilpatrick resigned in December, 1865.

A member of the Republican Party, Kilpatrick was Minister to Chile (1866-68) but broke with the party when he supported Horace Greeley for the presidency in 1868. Hugh Kilpatrick was reappointed to Chile and died in Santiago in 1881.