Emergency response team (ERT) member characteristics that contribute to High Reliability performance during patient care resuscitation events or other Critical Incident Management Situations are poorly understood. Findings from this study describe individual characteristics that experienced interprofessional ERT members perceive as contributing to High Reliability performance within the critical incident management context. This study supports the need for interprofessional research about emergency response teams’ High Reliability in hospital-based settings. ERT High Reliability, or “better than expected” team performance has been linked to overall patient care and safety. The purpose of this study was to identify and describe individual team member characteristics that contribute to High Reliability performance of ERT members and the overall emergency response team in a naturalistic setting during Critical Incident Management Situations. Using a qualitative descriptive design, data collection included participant observations, field notes, and interviews. Narrative data were audio-taped, transcribed and coded using Ethnograph v6©. Data content were analyzed thematically using inductive interpretive methods. Two major domains derived from the data were Self-Regulation and Whole-Team Regulation. The overarching theme, Orchestrating High Reliability at the Edge of Chaos, encompassed characteristics contributing to High Reliability performance of the ERT during Critical Incident Management Situations.