Chris grew up in Vault 34 and was a vault engineer. He was often sent to work on the reactor, which he believed would turn him into a ghoul. Eventually his hair began falling out due to natural reasons, but Chris insisted he was becoming a ghoul and subsequently left the Vault. This could have caused the reactor in Vault 34 to become unstable and leak the dangerous radiation, turning all the residents into ghouls.
Believing himself to be a ghoul, Chris joined the Bright Brotherhood (who could not convince him that he was human) in 2279 to help them accomplish their goal. He helps work with the technology in order to get the rockets up and running. When he discovers he will not be attending the Brotherhood in their flight, you can either help him destroy their plans to take flight, or you can convince Chris to continue helping ghouls (helping him will result in negative Karma, and helping the ghouls will result in positive Karma).
The player can convince Chris that he is indeed human with a speech check (50) or with the Black Widow perk, and the rest of the Bright Brotherhood are going on the rockets without him. They are then given the choice to help him sabotage the rockets so the ghouls die in flight. Alternatively, through extensive dialogue you can convince Chris not to sabotage the rockets, he will then accept the ghouls and send them off with no hard feelings before heading for Novac.
Because he thinks he's a ghoul, Chris calls the player Smoothskin and speaks rudely to the Courier. He also naturally speaks in the distinct gravelly voice that is typical of ghouls.
After the quest is over, he can be found milling about Novac. If the player talked Chris out of his hard feelings for the ghouls before the launch, but then sabotaged the controls anyway, Chris will remark that he was lucky not to have been on the rockets. If the player admits to sabotaging the controls, Chris will yell, "You bastard! Those ghouls declared me a saint!" and then turn hostile. Though he carries a 10mm pistol, he won't fight back.
xbox360pcps3 After completing the quest without convincing him of his humanity, he may simply say "Not now, its almost time for the Great Journey." over and over again without acknowledging the fact that they've already left without him. This can happen even if you convince him of his humanity through speech checks. If this happens, he will remain in the control room indefinitely rather than moving to Novac. In order to avoid this bug, make sure to first convince Haversam that he is human (make sure that's the first dialogue you make with him), and then its safe to start his quests (gather thruster and then the green substance). An alternate solution is as followed. After handing over the 2nd item and telling Haversam to start, Jason Bright will start his speech. Player MUST wait (and listen) until Jason will finish his speech. After that Haversam will run to the exit. The bug can happen even if you convince Chris he is human before starting his quests. If Jason's speech still gets cut off and Chris stays stuck in the basement, before telling Chris to initiate the rocket launch, pick the dialogue option to delay the launch instead, leave the area, wait, then speak to Chris again, this seems to fix the bug, Jason will give his full speech, then Chris will run for the exit afterward. [verified]
ps3xbox360 If Chris is killed after telling him to begin the launch, but before the launch itself, his body will appear in Novac. [verified]
ps3xbox360 If Chris is talked to during the end of the mission "Come fly with me" Chris may walk out of the control room and fall through the floor making the mission impossible to complete. [verified]