 After the outbreak of the Spanish–American War he dropped out of Lafayette and enrolled at the United States Military Academy (in 1942 Lafayette awarded Herr its honorary doctorate).In 1901 he and four other cadets were dismissed from the Academy after a hazing incident, but Herr fought for his reinstatement, returned to the Academy and graduated in May 1902.He was assigned to the 7th Cavalry Regiment and served with this regiment in Chickamauga, Georgia, the Philippines, and Fort Riley.