ObjectivesTo understand whether and how effective integration of health and social care might occur in the context of major system disruption (the COVID-19 pandemic), with a focus on how the initiative may overcome past barriers to integration.DesignRapid, descriptive case study approach with deviant case sampling to gather and analyse key informant interviews and relevant archival documents.SettingThe innovation (‘COVID-19 Protect’) took place in Norfolk and Waveney, UK, and aimed to foster integration across highly diverse organisations, capitalising on existing digital technology to proactively identify and support individuals most at risk of severe illness from COVID-19.ParticipantsTwenty-six key informants directly involved with project conceptualisation and early implementation. Participants included clinicians, executives, digital/information technology leads, and others. Final sample size was determined by theoretical saturation.ResultsFour primary recurrent themes characterised the experiences of diverse team members in the project: (1) ways of working that supported rapid collaboration, (2) leveraging diversity and clinician input for systems change, (3) allowing for both central control and local adaptation and (4) balancing risk taking and accountability.ConclusionsThis rapid case study underscores the role of leadership in large systems change efforts, particularly in times of major disruption. Project leadership overcame barriers to integration highlighted by prior studies, including engaging with aversion to clinical/safety risk, fostering distributed leadership and developing shared organisational practices for data sharing and service delivery. These insights offer considerations for future efforts to support strategic integration of health and social care.