Correctional officers occupy key positions of power and influence in prisons, yet experience massive stress and perceive themselves as vulnerable. Existing research outlines the significant mental health challenges officers face, but there is limited information on exactly how mental health concerns influence officer behavior on a day-to-day basis. I draw on ethnographic observations and semi-structured interviews with 131 Canadian provincial correctional officers, to demonstrate that stress, perceptions of vulnerability, and tension between management and staff strongly influence officer behavior. My participants outline common officer narratives relating to mental health, posttraumatic stress disorder (PTSD), and even suicide. In addition, a portion of officers describe using substances to manage stress. I detail how these narratives influence officer behavior toward prisoners, managers, other officers, and people outside prison. I conclude by examining existing mental health programming for officers and assess what steps correctional administrators can take to address common concerns.