On September 24, 1861, Anthony Beers enlisted in the 11th PA Cavalry Regiment, Company H and became a private. The Unit was nicknamed Harlan's Light Cavalry.
On December 17, 1861, he was promoted to the rank of corporal. He attained the rank of sergeant on July 17, 1862. He became a first sergeant on July 1, 1863.
Anthony joined the officer corps on June 14, 1864 as a second lieutenant. While serving as a second lietenant, Anthony was captured near Fort Harrison just after the fort was taken by the infantry. He was takend prisoner during the skirmishing actions. His cavalry unit suffered severe casaulties during the action. Fort Harrison is locted several miles south of Richmond, VA. He became a prisoner of war on October 7, 1864. He was imprisoned at Danville Prison in Southern Virginia. Anthony Beers survived the ordeal and was freed during the prisoner exchange on February 22, 1865. Shortly before his release from prison, he was brevetted as a Captain on March 13, 1865. His offical title, at the time, was Brevet Captain Anthony Beers 108th PA Infantry.
He was recommissioned as a captain in the 108th PA Cavalry Co H on May 5, 1865. He was mustered out of service on August 13, 1865.