Henry Wager Halleck was born at Westernville, in Oneida County, New York on January 16, 1815. He was the third of fourteen children of Joseph Halleck and Catherine Wager Halleck. Not enamored with the farming life of his family, Halleck ran away from home at an early age, and his uncle, David Wager, raised him in Utica, New York. Halleck attended Hudson Academy and Union College before receiving an appointment to the United States Military Academy in 1835. He graduated from the Academy in 1839, third in his class, and received an appointment as a brevet second lieutenant in the United States Army Corps of Engineers in July 1839.
U.S. Army Officer
Halleck stayed at West Point after his graduation, serving as an assistant professor of engineering from July 6, 1839 until June 28, 1840. After his tenure at West Point, Halleck held several engineering assignments. In 1845, the army promoted Halleck to first lieutenant, and he presented a series of lectures on the science of war. His lectures were published in 1846 under the title Elements of Military Art and Science. Volunteer officers widely used the work as a textbook during the American Civil War.
At the outbreak of the Mexican-American War (1846–1848), the army deployed Halleck to California, where he served as an engineering officer. During that conflict, Halleck received a brevet promotion to captain on May 1, 1847. From August 13, 1847 to December 20, 1849, Halleck served as secretary of state of the military government of California. In 1849, he was a member of the convention to form, and of the committee to draft, the constitution of the State of California.
Officials promoted Halleck to captain on July 1, 1853, but he left the army on August 1 of the next year to practice law and pursue other private interests in California.
On April 10, 1855, Halleck married Elizabeth Hamilton, the granddaughter of Alexander Hamilton. For the next six years, the couple lived in California, where Halleck managed one of the more prominent law firms in San Francisco, and he became an affluent landholder.
Department of the Missouri
When the American Civil War erupted, Halleck volunteered for service. The War Department re-commissioned him as a major general in the regular army on August 19, 1861. Halleck’s first Civil War assignment was in St. Louis as commander of the Department of the Missouri from November 9, 1861 through March 11, 1862. Immediately upon assuming his command, Halleck went about organizing his department and securing Missouri for the Union. By early 1862, he launched an offensive against the Confederacy in the West. In February, his most aggressive subordinate, Brigadier General Ulysses S. Grant, captured Fort Henry on the Tennessee River, and Fort Donelson on the Cumberland River, opening the way for a Union thrust into the Deep South.
Battle of Shiloh
Halleck’s successes brought greater responsibilities. On March 11, 1862, federal officials folded the departments of Kansas and Ohio into Halleck’s command. Officials renamed the combined department, which encompassed all the territory between the Appalachian Mountains and the Rocky Mountains, the Department of the Mississippi. Shortly thereafter, Halleck ordered the two principal armies under his command (the Army of the Tennessee, led by Grant, and the Army of the Ohio, led by Major General Don Carlos Buell) to merge at Pittsburg Landing, Tennessee to continue the Union’s drive south.
Before the armies united, Confederate Generals Albert Sidney Johnston and P. G. T. Beauregard launched a surprise attack against Grant that nearly routed the Army of the Tennessee. Reinforced by Buell’s army the following day, Grant rallied his troops and repulsed the Rebel offensive. Despite the Union victory at the bloody Battle of Shiloh (April 6-7, 1862), Halleck relieved Grant of his field command and assumed direct command of the federal forces in his department.
Siege of Corinth
Throughout April and May, Halleck slowly advanced against the strategic Confederate rail center at Corinth, Mississippi. On May 30, 1862, after a two-day siege, Halleck captured Corinth with almost no bloodshed. The victory was hollow though because Beauregard orchestrated an elaborate ruse that enabled the entire Confederate army trapped at Corinth to escape.
General-in-Chief of the Armies
Despite Beauregard’s escape, Halleck’s overall performance in the West impressed President Abraham Lincoln. On July 11, 1862, Lincoln ordered Halleck to Washington to serve as General-in-Chief of all the armies of the United States, effective July 23. Upon arriving in Washington, Halleck proved to be a better staff officer than field general. Halleck excelled at organizing and administering the army, but he lacked the aggressiveness that Lincoln desired.
By the spring of 1864, it was clear that a change was needed. On March 12, Congress resurrected the grade of lieutenant-general and conferred it upon Grant. The promotion created the untenable situation of Halleck commanding an officer of higher rank. Lincoln’s solution was to “promote” Halleck to the position of Chief of Staff, an administrative role in which Halleck served admirably. For the rest of the war, Halleck, the administrator, complemented Grant, the warrior, ensuring that the federal armies in Virginia, Georgia, and Eastern Tennessee were adequately equipped and reinforced.
Post-war Military Assignments
Following the war, Halleck held a series of commands, including the Military Division of the James (April 22-July 1, 1865), the Military Division of the Pacific (August 30, 1865-August 12, 1866), the Division of the Pacific (August 12, 1866-June 1869) and the Division of the South (June 17, 1869-January 9, 1872).
Halleck died in Louisville, Kentucky on January 9, 1872, while serving as commander of the Division of the South. He was buried at Green-Wood Cemetery, Brooklyn, New York.