Punctuated equilibrium, a theory of unexpected and sudden change arising out of evolutionary biology and paleontology, has been applied to decision sciences, physics, organizational theory, and group behavior but never to leadership emergence theories. The purpose of the study was to discover how leadership emerges during a period of punctuated equilibrium, a sudden and unexpected change event, using a naturalistic decision making framework. Thus, the research question probed how leadership emergence could be theoretically modeled in a critical event. This grounded theory study was particularly unique because it drew from, and helped unify the four scientific foundations of complexity science, leadership emergence, punctuated equilibrium theory, and naturalistic decision making. Data from 40 retrospective accounts, described in 15 interviews with critical incident intervention specialists, first responders, and wilderness leadership trainers residing in the northeastern region of the U.S. were supplemented by survey and observational data. Initial analyses employed a reflective coding matrix and a concept identification chart. Analysis of synthesized themes identified an event continuum model in which instinct, compassion, and responsibility served as motivating factors for leadership emergence that appeared in close proximity to the change event. Subsequent observable indicators of leadership emergence often included a sense of calm, quick situational assessment, and the tendency of individuals to ignore physical risk. This study found that punctuated equilibrium stimulated leadership emergence in individuals. The most profound implication for social change was that leadership arose in a time of need guided by compassion and a profound sense of responsibility toward one another regardless of formal position in the group.