Sheridan was born in Albany, New York, but grew up in Ohio. He graduated from West Point in 1853 near the bottom of his class, having missed a year after assaulting a fellow cadet with a bayonet. Sheridan led troops at the Mexican border and hastened the collapse of the regime of Emperor Maximilian of Mexico.
Recognizing Sheridan's aggressive spirit, General Ulysses S. Grant gave him command of his cavalry in 1864, and soon after of the Army of the Shenandoah Valley, Virginia. Sheridan laid waste to the valley, cutting off grain supplies to the Confederate armies.
Many Northerners regarded he devastation he brought to the Shenandoah Valley as military necessity, but to Southerners it was needless destruction. His policies — and those of William Tecumseh Sherman — had a brutal effectiveness — they destroyed the Confederate will to fight.
In the final stage of the war, Sheridan forced General Robert E. Lee to retreat to Appomattox Courthouse and surrender.
Sheridan served as military governor of Texas and Louisiana during Reconstruction; his policies toward former Confederates were so harsh, with charges of "absolute tyranny," that he was removed by President Andrew Johnson.
He was transferred to the Department of Missouri in 1867. He was to confine Great Plains Native Americans to reservations. His campaign was brutal. It saw excesses of killing and routine breaking of treaties as whites settled on native lands. He attacked the natives in their camps in the winter, expecting — correctly — that this would give him the element of surprise, taking advantage of the scarce forage the natives had for their horses. He once remarked, "If a village is attacked and women and children killed, the responsibility is not with the soldiers but with the people whose crimes necessitated the attack."
There is a widely-told story of Sheridan's campaign against the natives. Some natives reputably told Sheridan, "We're good Indians," to which Sheridan is often quoted as having replied, “The only good Indians I ever saw were dead.” He later denied ever saying it.
His policies showed him worthy of it. His victories were sometimes regarded massacres; he attacked Chief Black Kettle, on reservation soil, a peaceful chief. It had a brutal effectiveness, persuading other bands to quit their traditional ways and moved to the reservations.
He was commanding general of the United States Army from 1884 to his death in 1888.
The M551 Sheridan tank is named after General Sheridan. Early life and the Mexican War
The American Civil War
Reconstruction
Campaigns against the Native Americans
Final days
His legacy