Sheridan was born to John and Mary Sheridan, immigrants from County Cavan, Ireland. He grew up in Somerset, Ohio. In 1848, a family friend obtained an appointment for him at West Point. In his third year, he was suspended for a year for fighting with fellow cadet and future Union general,
William R. Terrill. After a perceived insult, Sheridan had threatened to run a bayonet through Terrill. He graduated 34 out of 52 in his class, in July 1853. After graduation, he was assigned to the 1st Infantry at Fort Duncan, Texas, serving on the frontier along the Rio Grande. He then went to the 4th Infantry in the Pacific Northwest. There, he performed duty at the Grand Ronde Indian Reservation in Oregon, where he fought against Native Americans.
At start of the Civil War, Sheridan was assigned as Chief Quartermaster of the Army of Southwest Missouri. Feeling that he would be a better field commander than a support officer, he got an appointment as a Colonel with the 2nd Michigan Volunteer Cavalry. At the Battle of Booneville, July 1, 1862, he held back several regiments of Brigadier Gen. James R. Chalmers' cavalry. Because of his impressive actions, he was promoted him to Brigadier General and assigned command of the 11th Division, III Corps, Army of the Ohio.
On December 31, 1862, the first day of the Battle of Murfreesboro, Sheridan held back the Confederate advance until his ammunition ran out and he was forced to withdraw. For these actions, he was promoted to major general and put in charge of the 2nd Division, IV Corps, Army of the Cumberland. In 6 months, he had risen from captain to major general.
At the Battle of Chickamauga, Sheridan, along with the rest of the army, was forced to withdraw after 2 days of heavy losses. During the Siege of Chattanooga, at the Battle of Missionary Ridge, Sheridan took the initiative and broke through the Confederate lines. Major Gen. Ulysses S. Grant, newly promoted to be General -in-Chief of the Union armies, decided he wanted Sheridan when he went east.
In March 1864, Grant assigned Sheridan to command the Cavalry Corps of the Army of the Potomac. During the Overland Campaign, he fought at the Battle of the Wilderness and Spotsylvania Court House. From May 9–24, Grant sent him on a raid toward Richmond. The raid was less successful than hoped, although his soldiers managed to kill Major Gen. J.E.B. Stuart at Yellow Tavern. Rejoining the Army of the Potomac, Sheridan's cavalry excelled at the Battle of Haw's Shop. Sheridan seized Cold Harbor and withstood a number of assaults until reinforced.
All during the war, the Confederacy sent armies through the Shenandoah Valley to threaten Washington, D.C., and sent raids throughout Maryland and Pennsylvania. In August, Grant organized the Army of the Shenandoah. He put Sheridan in charge of the army to drive Major Gen. Jubal A. Early out of the Shenandoah Valley and close it as a route to Washington, D.C.
Sheridan beat Early at the battles of Third Winchester and Fisher's Hill. In the final battle, at Cedar Creek, he rallied the troops who were retreating after a surprise attack. Early was defeated and Sheridan ordered the total destruction in the Shenandoah Valley. This made him the object of tremendous Confederate hatred and resentment, although he defended the action as necessary to end the war. He received a Thanks of Congress for this victory and was promoted to major general in the Regular Army.
Sheridan rejoined the Army of the Potomac in March 1865. At the Battle of Waynesboro, he trapped the remainder of Early's army and 1,500 Confederate soldiers surrendered. On April 1, he cut off Gen. Robert E. Lee's lines of support at the Battle of Five Forks, forcing Lee to evacuate Peterburg. President Abraham Lincoln sent Grant a telegram in April 7: "Gen. Sheridan says 'If the thing is pressed I think that Lee will surrender.' Let the thing be pressed." At Appomattox Court House, Sheridan blocked Lee's escape, forcing Lee to surrender later that day.
After the war, Sheridan was assigned to the Military Division of the Gulf, dealing with the sensitive state of affairs resulting from conflicts between the Mexican liberals and French-supported Maximilian. He was under the Monroe Doctrine to "observe" the disputes between the French forces of Napoleon III, and the Mexican republicans. His presence, U.S. political pressure, and the growing resistance of Benito Juárez induced the French to not press their claims over Mexico. Napoleon III withdrew his troops in 1866.
In 1866, Sheridan was appointed military governor of the Fifth Military District, which included the states of Texas and Louisiana. He severely limited voter registration for former Confederate soldiers and then required that only registered voters (including black men) be eligible to serve on juries. On July 30, while Sheridan was out of town, a white mob broke up the state constitutional convention in New Orleans, killing 34 blacks. Shortly after he returned, he wired Grant, "The more information I obtain of the affair of the 30th in this city the more revolting it becomes. It was no riot; it was an absolute massacre." An inquiry implicated the Mayor of New Orleans and President Andrew Johnson. Sheridan relieved the mayor. The governors of Texas and Louisiana complained so much that he finally removed them. Within a month of the Texas governor's firing, President Johnson removed Sheridan.
Under pressure from the various governors in the Great Plains, Grant appointed Sheridan to head the Department of Missouri in 1867. His first task was to end the Indian Wars by to getting the Indians to abide by their treaties or by the newly signed ones. In the Winter Campaign of 1868–69, Sheridan attacked the Indians in their winter quarters, taking their supplies and livestock and killing those who resisted. This strategy was to continue until the Indians abided their treaties. The Indian raids subsided during the 1870's and by the early 1880's, the Indian raids were almost over.
There was a story attributed to Sheridan during his Indian campaign. Some Indians told Sheridan, "We're good Indians," to which he replied, "The only good Indians I ever saw were dead." The story is of questionable authenticity and Sheridan always denied the quote.
In 1870, the Secretary of War authorized Sheridan to observe and report on the Franco-Prussian War. As a guest of the King of Prussia, he was able to observe the planning and execution of some of the battles. He toured most of Europe after his inspection of the military affairs of the Franco-Prussian War.
In 1871, Sheridan took several companies of troops to Chicago during the "Great Chicago Fire". The mayor, to calm the panic, put the city under martial law, and issued a proclamation putting Sheridan in charge. In 1883, Sheridan succeeded Major Gen. William T. Sherman as Commander-in-Chief of the Army and held that position until shortly before his death.
The protection of the Yellowstone area was Sheridan's personal crusade. In 1875, he promoted military control of the area to prevent destruction of natural formations and wildlife. A rider was added to the Sundry Civil Bill of 1883, giving Sheridan and his supporters almost everything they had asked. In 1886, after a string of ineffectual and sometimes criminal superintendents, he ordered the 1st Cavalry into the park. The military operated the park until the National Park Service took it over in 1916.
On June 3, 1875, Sheridan married Irene Rucker, a daughter of a long time army officer, and they had 4 children. After the marriage, he and his wife moved to Washington, D.C. They lived in a house given to them by Chicago citizens in appreciation for his protection of the city after the 1871 fire.
In June 1888, shortly before his death, Sheridan was confirmed as General of the Army. He was fearless in all his endeavors and always had the loyalty of the many men who served under his command.
After Sheridan died, his body was returned to Washington and he was buried in Arlington National Cemetery. He finished his "Personal Memoirs" only 3 days before he died.
Captain- May 14, 1861
Colonel - May 25, 1862
Brigadier General USV- July 1, 1862
Major General USV- December 31, 1862
Brigadier General USA- September 20, 1864
Major General, USA- November 8, 1864
Chief Quartermaster and chief commissary of Subsistence, Army of Southwest Missouri, Department of the Missouri (ca. December 25, 1861-early 1862)
2nd Brigade, Cavalry Division, Army of the Mississippi (June 1-September 4, 1862)
11th Division, Army of the Ohio (September-September 29, 1862)
11th Division, III Corps, Army of the Ohio (September 29-November 5, 1862)
3rd Division, Right Wing, XIV Corps, Army of the Cumberland (November 5, 1862-January 9, 1863)
3rd Division, XX Corps, Army of the Cumberland (January 9-October 9, 1863)
2nd Division, IV Corps, Army of the Cumberland (October 10, 1863-February 17, 1864 and February 27-April 1864)
Cavalry Corps, Army of the Potomac (April 4-August 2, 1864)
Army of the Shenandoah (August 6-October 16, 1864 and October 19, 1864-February 28, 1865)
Middle Military Division (August 6, 1864-February 27, 1865)