In this study, we examine the political leaders’ communication style and its influence on the public behaviour about the COVID-19 crisis. We attempt to achieve our research objective by investigating the cases of Lee Hsien Loong in Singapore and Donald Trump in the United States (US). Using an inductive theory-building approach, nested multi-case study research design, we explore the relationship between political leaders’ communication style and public behaviour about COVID-19 crisis from a communication-centred perspective. We collect both social media data from political leaders and individual check-in data from Singapore and US from January to June 2020. By adopting two-stage analysis, we find that Lee Hsien Loong’s use of “engaging” communication style in preventing the spread of COVID-19 led to a more significant decrease of the public movement in comparison to Donald Trump’s use of “champion of the people” communication style.