He graduated from the United States Military Academy at West Point, New York, and was commissioned a 2nd Lieutenant in the 6th U.S. Infantry on July 1, 1829.

Hoffman then moved south to Fort Jesup and Camp Sabine in Louisiana before fighting in the Second Seminole War from 1837 to 1842.

[2] On August 20, 1847, Hoffman was brevetted to major for gallant and meritorious conduct in the Battles of Contreras and Churubusco.

He was brevetted a lieutenant colonel on September 8, 1847, for his gallant and meritorious conduct in the Battle of Molino del Rey.

He was taken as a prisoner of war by the Confederates when Brigadier General David E. Twiggs surrendered the Union command on February 18, 1861.

[4] It was made directly responsible to the Secretary of War on June 17, 1862, so when Hoffman took the position, he had access to the top of the military and political structure.

[2] In addition, the army captured thousands of soldiers, whom they held as prisoners of war, transferring them away from the fronts to camps set up to house them.

On both sides, the prison camps were overcrowded, suffered food shortages and poor sanitation, and were plagued with infectious disease.

Release requests from Union officials, Confederate soldiers, and Southern family members came to Hoffman's office for review and evaluation.

Hoffman believed deserters, because they had already renounced their military obligation to the Confederacy, provided an opportunity to "reconstruct" the rebel soldiers and undermine the Confederate war effort.

[2] Military field commanders could administer the oath of allegiance to deserters if they could verify their stories and be assured they were not spies.

Hoffman narrowed the conditions for Confederates to take the oath of allegiance, and the number of prisoners released decreased dramatically.