Philip Henry Sheridan, United States Army officer, son of John and Mary (Meenagh) Sheridan, was born on March 6, 1831. His place of birth is uncertain, for Sheridan was apparently born sometime between his parents' emigration from Ireland and their settlement in Ohio; Ireland, Boston, Massachusetts, Albany, New York, and Somerset, Ohio, have each been suggested as Sheridan's birthplace. His father, an Irish Catholic, worked in turnpike construction after the family's arrival in Ohio. Young Sheridan received a basic education in local schools. He was appointed to the United States Military Academy in 1848 and graduated in 1853, thirty-fourth of fifty-two cadets. In 1854 he went to Fort Duncan, Texas, on the Rio Grande frontier, with the First United States Infantry. In late 1855 he was transferred to the Pacific Northwest, where he served until the Civil War started. In the war Sheridan was nicknamed "Little Phil" (he was only 5'5" tall) and became one of the top three northern heroes, along with Ulysses S. Grant and William T. Sherman. Though he was only a lieutenant in 1861, Sheridan was promoted to major general in 1864. He commanded divisions at the battles of Perryville, Kentucky (October 1862), Stones River, Tennessee (December 1862), Chickamauga, Georgia (September 1863), and Chattanooga, Tennessee (November 1863). In 1864 Grant made him commander of the cavalry corps of the Army of the Potomac in the eastern theater. He led a raid on Richmond, Virginia (May 1864), devastated the Shenandoah valley (August 1864-March 1865), and helped force the surrender of Robert E. Lee at Appomattox, Virginia (April 1865). After the war Grant ordered Sheridan to Texas with 50,000 soldiers to threaten the French-sponsored regime of Emperor Ferdinand Maximilian Joseph in Mexico. For more than a year Sheridan tried to persuade the French to leave Mexico.
Reconstruction became his primary task on March 19, 1867, when he assumed command of the Fifth Military District (Texas and Louisiana), with headquarters in New Orleans. Congressional Republicans, whom Sheridan supported, had passed a series of Reconstruction acts that required registering voters and writing new state constitutions in the states of the Confederacy. Furthermore, military-district commanders had authority to remove from office former Confederates and Democrats who resisted Reconstruction measures. Sheridan selected Gen. Charles Griffin as his subordinate in Texas. Sheridan, who was an advocate for freedmen, severely limited voter registration for former Confederates and then required that only registered voters (including black men) be eligible to serve on juries. Most of Sheridan's political appointees were staunch Unionists or Republicans. Griffin urged the removal of the governor of Texas, James W. Throckmorton, a former Confederate, on the grounds that he had been "disloyal." Sheridan had removed many civilian officials but hesitated to take out a governor. Soon, however, he replaced the governor of Louisiana and then removed Governor Throckmorton on July 30, 1867, as an "impediment to the reconstruction of the State." Within a month Sheridan himself was transferred from the Fifth District, on the orders of President Andrew Johnson. Sheridan had taken steps to change government and politics in Texas drastically. Of his successors, Joseph A. Mower and Joseph J. Reynolds also worked on behalf of the Republican party, but Winfield Scott Hancock tried to aid the Democrats.
Sheridan next commanded the Department of the Missouri, with headquarters at Fort Leavenworth, Kansas, where he organized a successful winter campaign (1868–69) led by Lt. Col. George A. Custer against the southern Cheyennes in Indian Territory. In 1869 Sheridan became commander of the Military Division of the Missouri, with headquarters at Chicago, Illinois. He directed that five army field forces converge on the Texas Panhandle, in a campaign that was to be the largest single action against the Comanches and Kiowas. It was a remarkable success, especially the victory of Col. Ranald S. MacKenzie at Palo Duro Canyon on September 28, 1874 (see RED RIVER WAR). On June 3, 1875, Sheridan married Irene Rucker, daughter of Gen. Daniel H. Rucker. After William T. Sherman retired on November 1, 1883, Sheridan became commanding general of the United States Army, and on June 1, 1888, Congress promoted him to full general. His own version of his eventful career appeared in his Personal Memoirs (2 vols., 1888). Sheridan died of heart disease at Nonquitt, Massachusetts, on August 5, 1888, while still on active duty.