Later that same night, he lied about his age and enlisted in the U.S. Army. Panzram left for boot camp, which at that time was held in Fort William Henry Harrison, a distant post in western Montana. He was assigned as a private to Company A in the 6th Infantry. On his first day in uniform, Panzram was brought up on charges of insubordination for refusing a work detail. Over the next month, he was jailed several times for various petty offenses. Constantly drunk and impossible to control, Panzram was unable to conform to military discipline.
In April 1908, he broke into the quartermaster’s building and stole a quantity of clothes worth $88.24. As he attempted to get away with the stolen items, he was arrested by the military police and thrown in the stockade. He received a general court martial on April 20, 1908, before a military tribunal of nine junior and senior officers who had no tolerance for criminal activity from men in uniform. Panzram pleaded guilty to three counts of larceny.