Sherman was born in Lancaster, Ohio. He graduated from the United States Military Academy at West Point in 1840 and served in the United States Army for 38 years. He fought in the Mexican–American War and the Seminole Wars, and held various other assignments before the Civil War.
At the start of the Civil War, Sherman served in Kentucky and Tennessee, where he gained attention for his aggressive tactics and earned the nickname "Billy Yank". He was one of the Union generals involved in the bloody battle of Shiloh in April 1862.
In early 1863, Sherman was given command of the XV Corps in the Army of the Tennessee, which he led in the Vicksburg Campaign. He later commanded the Army of the Tennessee in the Chattanooga Campaign, where he led the successful assaults on Missionary Ridge and Lookout Mountain.
Sherman made his famous march through Georgia and the Carolinas in 1864–65, which culminated in the capture of Columbia, South Carolina, and the surrender of the Confederate army under General Robert E. Lee. Sherman's march is often credited with hastening the end of the war.
After the Civil War, Sherman served as the Commanding General of the United States Army from 1869 to 1883. He also served in Congress, representing Ohio from 1875 to 1881. Sherman died in New York City in 1891.
Sherman was a controversial figure during his lifetime and remains so today. His military tactics, especially his use of scorched-earth warfare during his march through Georgia and the Carolinas, were criticized by some at the time and continue to be debated by historians. However, there is no doubt that Sherman was one of the most successful and influential generals of the Civil War.