Since the beginning of the COVID-19 pandemic, few studies have focused on crisis management of multiple services within one hospital over several waves of the pandemic. The purpose of this study was to provide an overview of the COVID-19 crisis response of a Parisian referral hospital which managed the first three COVID cases in France and to analyze its resilience capacities. Between March 2020 and June 2021, we conducted observations, semi-structured interviews, focus groups, and lessons learned workshops. Data analysis was supported by an original framework on health system resilience. Three configurations emerged from the empirical data: 1) reorganization of services and spaces; 2) management of professionals' and patients' contamination risk; and 3) mobilization of human resources and work adaptation. The hospital and its staff mitigated the effects of the pandemic by implementing multiple and varied strategies, which the staff perceived as having positive and/or negative consequences. We observed an unprecedented mobilization of the hospital and its staff to absorb the crisis. Often the mobilization fell on the shoulders of the professionals, adding to their exhaustion. Our study demonstrates the capacity of the hospital and its staff to absorb the COVID-19 shock by putting in place mechanisms for continuous adaptation. More time and insight will be needed to observe whether these strategies and adaptations will be sustainable over the coming months and years and to assess the overall transformative capacities of the hospital.