Skinner is a former Marine and a Vietnam War veteran. In the war he once killed a boy at a very short distance, an experience which has scarred him for life. He is married to Sharon Skinner. He has been treated at a sleep disorder clinic, suffering from recurring dreams of an old woman, which may either be a hallucination arising from drug use during Vietnam or a succubus. Skinner's hobbies include jogging and boxing, the latter of which has been shown in his ability to outfight Fox Mulder and X and to defend himself reasonably well when he was attacked by Alex Krycek and his men.