He is bitterly whiling away the hours until he can find out who is responsible for the disappearance of his wife, Carla, and kill them. Hardened and psychologically troubled from his time in the NCR military, Boone vacillates between being a stone-cold killer and a decent human being. Venturing out from the relative safety of Novac brings Boone into close contact with his old life until he is forced to deal with the tragic events that caused him to leave the military.Boone met Carla while on leave on the New Vegas Strip. Carla was the only thing in the world who made him feel calm and happy in life. When he listened to her, she made him forget about everything he did in the military. He left the military, married Carla, and moved to Novac at the invitation of his 1st Recon friend, Manny Vargas. Jeannie May Crawforddescribes Carla as a "cactus flower": pretty to look at, but hard to get close to. She was never content with the ordinary life of the small town. Carla's attitude toward the town caused distance between Boone and Manny, which continued after Carla's disappearance. She had been kidnapped by the Legion, and Boone suspected she was betrayed by one of the townsfolk.

After completing several quests with Boone as a follower, it is possible to gain more information about Boone's wife. When she was kidnapped, he tracked down the slaving party in hopes of rescuing her, only to find her being auctioned off with hundreds of other slaves to Legion soldiers. All Boone had was his rifle and the distance between them. Instead of subjecting her to the horrors of Legion slavery, he chose to take her life in a mercy killing. As a result of the psychological trauma Boone endured, he has become suicidal; he has no goal, purpose, or desire in life but to slaughter Legionaries (preferably by assisting with cranial perforation) until the Legion finally catches up to him. Boone also reveals he was part of the NCR attack on Bitter Springs, where he and his squad were ordered to shoot members of the Great Khans, including women, children, and the sick.

Craig Boone, despite leaving the military, is still an NCR soldier at heart; he refuses to work with a terrorist against the NCR and will not tolerate the Courier working with Caesar's Legion. In fact, if the player enters the Fort with Boone, all Legion members will become immediately hostile, regardless of the player's previous standing with them.