High Quality Content by WIKIPEDIA articles! FBI Assistant Director Walter Sergei Skinner is a fictional character in the American FOX television shows The X-Files and The Lone Gunmen, two science fiction shows about a government conspiracy to hide or deny the truth of Alien existence. Skinner supervised the X-Files office, which is concerned with cases with particularly mysterious or possibly supernatural circumstances that were left unsolved and shelved by the FBI. Fox Mulder, the FBI agent in charge of the X-Files, considers the X-Files the truth behind the supposed conspiracy. Portrayed by Italian-American actor Mitch Pileggi, Skinner was a main character in the ninth season of the show and a recurring character throughout the first eight seasons.