At some point prior to 2262 Clemens served with fellow Earthforce officer Elizabeth Lochley. During the Earth Alliance Civil War Clemens held the rank of Major and was in charge of the prison system on the Beta 7 colony. It is assumed that he was responsible for the murder and torture of dissidents on Beta 7 and elsewhere. After the death of President Clark he became wanted and went underground in order to escape apprehension.
Blaming Sheridan for destroying his life, career and family and having nothing too lose, Clemens was determined to kill Sheridan during his swearing-in as President of the then newly founded Interstellar Alliance. Drawing from his experience as a trained infiltrator he disguised himself as a Gaim ambassador to attend the inauguration ceremony, but was prevented from shooting Sheridan by one of the rogue telepaths that had just arrived on the station. Despite being wounded on this first attempt he managed to steal one of the station's Starfuries and threatened to shoot Sheridan from space. He was finally stopped by Garibaldi sneaking up on him in a Starfury, and killed when his ship was destroyed by the station's defenses.
- His Earthforce record gives his serial number as "8910290-SOL-2" and shows that he became a qualified Starfury pilot on the 17th of July, 2249.