After graduating from West Point and a brief service in the United States Army, he became the first Superintendent of the Virginia Military Institute on its establishment in 1839, and held that post until shortly before his death.

His superintendency included the four years of the American Civil War, during which he served as a major general in the Virginia militia and a colonel in the Confederate States Army.

[1] When the Virginia Military Institute was established in Lexington, board of trustees member John Thomas Lewis Preston successfully recruited Smith to be the school's first superintendent.

Major General John C. Breckinridge was commanding Confederate forces in the Department of Southwest Virginia during a critical time in the 1864 campaign in the Shenandoah Valley.

[5] Although he did not want to use the VMI cadets in battle, Breckinridge requested that Smith send them to reinforce his outnumbered army when Union forces began to move into the valley.

[13] On June 11, 1864, Major General David Hunter, who had replaced Sigel after New Market, ordered a retaliatory attack, his troops burning and shelling VMI's campus, forcing the relocation of classes to Richmond, where they remained until the city fell in April 1865.