This study of US Navy Sea Air and Land (SEAL) commandos contributes to research investigating mindfulness in high-reliability organizations (HROs) by identifying the indi- vidual and collective influences that allow SEALs to build capacity for mindful behaviors despite the complexity of their missions, the unpredictability of their operating environ- ments, and the danger inherent in their work. Although the HRO literature identifies a number of hallmarks of reliability, less attention is paid to how mindfulness is opera- tionally achieved in situ by individuals on the frontline working in HROs. This study addresses this gap using a multiphase, multimethod investigation of US Navy SEALs, identifying new links between individual mindfulness attributes (comfort with uncertainty and chaos) and collective mindfulness influences (a positive orientation towards failure) that combine to co-create a phenomenon we call “mindfulness in action.” Mindfulness in action occurs when HROs achieve an attentive yet flexible focus capable of incorporating multiple—sometimes competing—realities to assess alternative solutions and take action in dynamic situations. By providing a more nuanced conceptualization of the links be- tween individual mindfulness attributes and collective mindfulness influences, this paper opens up new avenues of discovery for a wide range of reliability-seeking organizations. For supporting media please see https://vimeo.com/153223681.