The coronavirus disease 2019 (COVID-19) pandemic mandated rapid, flexible solutions to meet the anticipated surge in both patient acuity and volume. This paper describes one institution’s emergency department (ED) innovation at the center of the COVID-19 crisis, including the creation of a temporary ED–intensive care unit (ICU) and development of interdisciplinary COVID-19–specific care delivery models to care for critically ill patients. Mount Sinai Hospital, an urban quaternary academic medical center, had an existing five-bed resuscitation area insufficiently rescue due to its size and lack of negative pressure rooms. Within 1 week, the ED-based observation unit, which has four negative pressure rooms, was quickly converted into a COVID-19–specific unit, split between a 14-bed stepdown unit and a 13-bed ED-ICU unit. An increase in staffing for physicians, physician assistants, nurses, respiratory therapists, and medical technicians, as well as training in critical care protocols and procedures, was needed to ensure appropriate patient care. The transition of the ED to a COVID-19–specific unit with the inclusion of a temporary expanded ED-ICU at the beginning of the COVID-19 pandemic was a proactive solution to the growing challenges of surging patients, complexity, and extended boarding of critically ill patients in the ED. This pandemic underscores the importance of ED design innovation with flexible spacing, interdisciplinary collaborations on structure and services, and NP ventilation systems which will remain important moving forward.