He was expelled from the Institute weeks before graduation in 1852 amidst a bitter dispute with then-mathematics professor Thomas Jackson, but was granted his degree in 1872 in recognition of his military service in the American Civil War.

Walker was born near Mount Meridian in Augusta County, Virginia on August 27, 1832.

Walker was again promoted, this time to colonel, in March 1862, leading his regiment in several actions.

However, after only four days, Walker was replaced by the more experienced Jubal Early, who was just returning to action after a wound suffered at Williamsburg two months earlier.

He led it during the Gettysburg Campaign, where the brigade participated in the attacks on Culp's Hill.

He was badly wounded at the Battle of Spotsylvania Court House in 1864 and sent home to recuperate.

When the war ended in 1865, Walker returned to his law practice and political career, being elected as a Democrat to the House of Delegates of Virginia in 1871 and 1872.

VMI granted him an honorary degree in 1872 in recognition of his Civil War service.

Walker died in Wytheville, Virginia on October 21, 1901; and was buried in the town's East End Cemetery.