John McAllister Schofield was born in Gerry, New York, on 29 September 1831 and at the age of 12 was taken by his father, a Baptist minister, to Freeport, Illinois and was educated in the public schools. He graduted from the United States Military Academy at West Point in 1853, ranking seventh in his class. He was commissioned second lieutenant in artillery and served in the South, 1854-1855 and was promoted to first lieutenant in August 1855. He was assistant professor of natural and experimental philosophy at West Point from 1855 to 1860; married Harriet Bartlett in 1857; taught physics at Washington University of St. Louis, 1860-1861 and was mustering officer for Missouri as the Civil War opened. He was major, 1st Missouri Volunteer Infantry, and captain, 1st Artillery, in Missouri operations. He was appointed brigadier general of volunteers and Missouri militia, November 1861, and major general of volunteers, November 1862; successively commanded the Missouri militia, 1861-1862, the Army of the Frontier, 1862-1863, the 3d Division of XIV Corps, 1863, the Department of the Missouri, 1863-1864, and the Department of the Ohio, 1864-1865; commanded the Army of the Ohio in the invasion of Georgia, including the battles of Kenesaw Mountain and Atlanta, 1864; commanded the XXIII Corps in Alabama-Tennessee operations, including the battles of Franklin and Nashville, 1864; was appointed brigadier general in the Regular Army, November 1864. He commanded the Department of North Carolina, 1865; was brevetted major general, March 1865. He served throughout the Civil War in command positions, receiving the Medal of Honor for heroism in battle.

He served as a confidential diplomatic emissary to France concerning withdrawal of French troops from Mexico, 1865-1866 and commanded the Department of the Potomac, 1867. He served as Secretary of War, 1 June 1868-13 March 1869 and was appointed major general, March 1869. He commanded the Department of the Missouri, 1869-1870 and commanded the Division of the Pacific, 1870-1876. He served on a special mission to the Hawaiian Islands to assess their military value in 1872-1873 and was the military officer who recommended that Pearl Harbor, Hawaii, be established as a military base by the United States. He was Superintendent of the United States Military Academy at West Point from 1876 to 1881. He successively commanded the Divisions of the Pacific (1882-1883), the Missouri (1883-1886), and the Atlantic (1886-1888).

He married his second wife, Georgia Kilbourne in 1891 and was commanding general of the entire United States Army from 14 August 1888 to 29 September 1895 following the death of Lieutenant General Philip S. Sheridan. He was instrumental in clarifying lines of authority and achieving harmony between staff and line, espoused increases in pay for noncommissioned officers, advanced a plan to reduce desertions, initiated efficiency reports on officers, and recommended that incompetent officers be denied promotion. He was promoted to lieutenant general, February 1895 and retired from active service on his 64th birthday, September 29, 1895. He died in St. Augustine, Florida, on 4 March 1906. He is buried in Section 2 of Arlington National Cemetery.

General Schofield's parents were James Schofield and Caroline McAllister. Caroline was a great grand daughter of the W18 family line progenitor, William McAllister, (W18 family line progenitor) who was born in Scotland about 1720/40. He emigrated to America, settling in Chatauqua County, New York James and Caroline Schofield had four sons and three daughters. One of John McAllister Schofield's brothers was George Wheeler Schofield, who was a Lieutenant Colonel in the Union Army during the Civil War.