Leading the first operation against Petersburg, Smith's caution, possibly illness-related, may have cost the Union a prime opportunity for a quick end to the war.

[3] He was educated locally in Vermont until he attended the United States Military Academy at West Point in 1841, and graduated four years later standing fourth of 41 cadets.

[3] During his service in the Corps, Smith conducted surveys of the Great Lakes, the states of Texas, Arizona, and Florida, as well as much of Mexico.

However, his indiscretion in communicating to Lincoln directly about Burnside's shortcomings, compounded by the fact that Smith was a close friend of out-of-favor Maj. Gen. George B. McClellan, resulted in his losing both his corps command and his rank; the Senate failed to confirm his nomination to major general, which expired on March 4, 1863.

Reverting to the rank of brigadier general, he commanded a division-sized force of militia within the Department of the Susquehanna in Pennsylvania during the critical days of the Gettysburg Campaign, repelling Maj. Gen. J.E.B.

On October 3, 1863, Smith was assigned to duty as chief engineer of the Army of the Cumberland (and a couple of weeks later, the Military Division of the Mississippi).

As such he conducted the engineer operations and launched the Battle of Brown's Ferry, which opened the "Cracker Line" to provide supplies and reinforcements to the besieged troops in Chattanooga.

Of this action the House Committee on Military Affairs reported in 1865 that "as a subordinate, General WF Smith had saved the Army of the Cumberland from capture, and afterwards directed it to victory."

[4] For the Overland Campaign of 1864, Smith was assigned by Grant to command the XVIII Corps in Maj. Gen. Benjamin Butler's Army of the James, which he led in the Battle of Cold Harbor and the first operations against Petersburg.

Smith spent the remainder of the war serving on military commissions, including one that discovered significant corruption in the Department of the Gulf.