Schools have become a common incident site for targeted mass violence, including mass shootings. Although exposure to mass violence can result in significant distress, most individuals are able to fully recover over time, while a minority develop more pervasive pathology, such as PTSD. The present study investigated how several pre- and post-trauma factors predict posttraumatic stress symptoms (PTSS) in both the acute and distal aftermath of a campus mass shooting using a sample with known levels of pre-trauma functioning (N = 573). While the largest proportion of participants evidenced resilience following exposure to the event (46.1%), many reported high rates of PTSS shortly after the shooting (42.1%) and a smaller proportion (11.9%) met criteria for probable PTSD both in the acute and more distal aftermath of the event. While several pre-shooting factors predicted heightened PTSS after the shooting, prior trauma exposure was the only pre-shooting variable shown to significantly differentiate between those who experienced transient versus prolonged distress. Among post-shooting predictors, individuals reporting greater emotion dysregulation and peritraumatic dissociative experiences were over 4 times more likely to have elevated PTSS 8 months post-shooting compared to those reporting less dysregulation and dissociative experiences. Individuals with less exposure to the shooting and greater satisfaction with social support were more likely to recover from acute distress. Results suggest that, while pre-trauma factors may differentiate between those who are resilient in the aftermath of a mass shooting from those who experience heightened distress, several event-level and post-trauma coping factors help distinguish between those who eventually recover and those whose PTSD symptoms persist over time.