With indiscriminate geographic and socio-economic reach, COVID-19 has visited destruction of life and livelihoods on a largely unprepared world and can arguably be declared the new millennium's most trying test of state capacity. Governments are facing an urgent mandate to mobilize quickly and comprehensively in response, drawing not only on public resources and coordination capabilities but also on the cooperation and buy-in of civil society. Political and institutional legitimacy are crucial determinants of effective crisis management, and low-trust states lacking such legitimacy suffer a profound disadvantage. Social and economic crises attending the COVID-19 pandemic thus invite scholarly reflection about public attitudes, social leadership, and the role of social and institutional memory in the context of systemic disruption. This article examines Hong Kong as a case where failure to respond effectively could have been expected due to low levels of public trust and political legitimacy, but where, in fact, crisis response was unexpectedly successful. The case exposes underdevelopment in scholarly assumptions about the connections among political legitimacy, societal capacity, and crisis response capabilities. As such, this calls for a more nuanced understanding of how social behaviours and norms are structured and reproduced amidst existential uncertainties and policy ambiguities caused by sudden and convergent crises, and how these can themselves generate resources that bolster societal capacity in the fight against pandemics.