Nursing homes face a high risk of coronavirus disease 2019 (COVID-19) infection; in the early stages of the pandemic, outbreaks in nursing homes resulted in significant deaths among residents. Our medical team intervened in one nursing home struggling to cope with the COVID-19 pandemic. We analyzed the outcomes of 65 residents (52 women and 13 men; mean age, 89 years) during the first wave of infection, as well as changes in resident and staff numbers after the pandemic subsided. The mortality rates in the early and late transfer groups for the first three months of our intervention were 46.7% and 19.2%, respectively. The number of residents and staff fell to 34 and six, respectively, at their lowest point, but recovered to 64 and 33, respectively, by August 2023. Since the successful containment of the outbreak, no clusters of COVID-19-related illnesses have been observed at the facility despite nine infection waves occurring across Japan. Improving staff precautions, designing facilities with effective zoning, and sharing information with government agencies are essential for preventing healthcare-associated infections. Hence, an interprofessional team approach is important to support residents, and ongoing mental health support for staff is essential to maintain optimal healthcare quality in nursing home facilities.