Returning to the Western Theater, Wilson became one of the few Union commanders to defeat Confederate cavalier Nathan Bedford Forrest in battle.

Wilson ended the war with his men capturing both Confederate President Jefferson Davis and Andersonville Prison commandant Henry Wirz in May 1865.

He attended McKendree College for a year and graduated from the United States Military Academy in 1860, sixth in his class of 41, receiving a commission as a brevet second lieutenant in the Topographical Engineers.

After the start of the Civil War, Wilson received promotions to second and first lieutenant and became the topographical engineer for the Port Royal Expeditionary Force, from September 1861 to March 1862.

As the topographical engineer for the Department of the South, he took part in the Battle of Fort Pulaski at the mouth of the Savannah River and received a brevet promotion to major in the regular army for his service.

Wilson was transferred to the Western Theater and joined Maj. Gen. Ulysses S. Grant's Army of the Tennessee as a lieutenant colonel and topographical engineer.

He continued on staff duty during the Battle of Chattanooga and was chief engineer of the force sent to relieve Knoxville under Maj. Gen. William T. Sherman.

During the first three days of their raid, Wilson's cavalry tore up 60 miles of track and burned two trains and several railroad stations.

The Confederacy had sensed its strategic importance, putting a small fort there under Captain Benjamin Farinholt, and his 296 reserve troops.

A valiant stand by local volunteers of old men and boys, with help from surrounding counties, gathered almost a force of nearly 1,000, which halted the 5,000 well-armed troops.

However, just before Sheridan's decisive Battle of Cedar Creek in October 1864, Wilson was upgraded to brevet major general of volunteers and transferred back to the West to become chief of cavalry for the Military Division of the Mississippi under Sherman.

Rather than accompanying Sherman, however, he and 17,000 troopers were attached to Maj. Gen. George H. Thomas's Army of the Cumberland for the Franklin-Nashville Campaign in November and December 1864.

Retiring from the Army, in 1902 he represented President Theodore Roosevelt at the coronation of Edward VII of the United Kingdom.