Health systems were abruptly plunged into a crisis as SARS-CoV-2 exploded into a pandemic in spring 2020. In March-April 2020, Metropolitan Detroit was a US "hotspot." As a large health system with five hospitals and two behavioural health inpatient facilities, a health insurance company, a medical group and physician network, and 41 ambulatory clinics normally hosting over 10,000 daily patient encounters, the Henry Ford Health System deployed numerous strategies in the management of this upheaval. As hospitals and Emergency Departments were inundated with COVID-19 patients, other services and activities needed to shut down as state-mandated policies were promulgated, new internal and external communication networks established, and management of employees and resources such as ventilators, ICU beds, personal protective equipment, and laboratory supplies became critical challenges. We describe herein the system-wide strategies implemented and lessons learned in the operation of a health system in the initial throes of a global pandemic.