During the Earth Alliance Civil War, Eisensen served on the EAS Damocles. In 2261, he evacuated the Damocles after the vessel was heavily damaged in battle against John Sheridan's forces during the Earth Alliance Civil War at Beta IX. He was picked up by the EAS Agamemnon while in a life pod. He gave information about President Morgan Clark's plan to ambush Commander Susan Ivanova's fleet in Sector 300 with Advanced Omega class destroyers in exchange for leniency in his part of the bombing of civilian targets on Beta IX. He informed Commander Ivanova that there are spies who "defected" that report regularly to Clark's forces.