The man with the unusual middle name was born outside Clyde, Ohio on November 14, 1828. His family poverty stricken, James became friends with a merchant who was able to get him into West Point. McPherson graduated first in his class in 1853.

Having a reputation as an excellent officer, he entered the Corps of Engineers. When the Civil War began, he first served as an aide to Major General Henry W. Halleck. Following this, he then was the chief engineer to major General Ulysses S. Grant during the Fort Henry and Fort Donelson campaigns, as well as the Battle of Shiloh and occupations in West Tennessee. On August 19, 1862, as a result of a recommendation from Halleck and Grant, McPherson was promoted to brigadier general. In October 1862 he was again promoted to major general, and in January 1863, he was assigned as commander of the XVII Corps under General Grant. During the Vicksburg Campaign and at the Battle of Champion's Hill on May 16, 1863, McPherson performed in an exceptional manner, taking the initiative in winning this battle.

In February 1864, his corps command was placed under Major General William T. Sherman during the Meridian Campaign. In March of 1864, Sherman succeeded Grant in the command of the Union forces in the West, so McPherson took over Sherman's former post as head of the Army of Tennessee. From time to time, General Sherman would use McPherson and his army on assignments intended to outflank the Confederates under the command of General Joseph E. Johnston. While on one of his maneuvers, McPherson was southeast of Atlanta, when Confederate General John B. Hood, who had replaced Johnston, delivered a surprise counterattack. On July 22, 1864, while returning from Sherman's headquarters with another officer, they went to investigate this action by Hood. While crossing a no-man's-land of sorts, McPherson ran into a group of Rebel skirmishers. While attempting to get away, McPherson was shot and killed.

McPherson was a brilliant officer who possessed high character. Admired by General Sherman, he once said that if the war lasted long enough, McPherson would have certainly surpassed Grant in reputation and ability. Because McPherson did not live long enough to prove himself as an independent commander, he can be remembered as one of the finest corps commanders in the Union army.