Hashtag activism and connective action: A case study of #HongKongPoliceBrutality

•Three information sharing mechanisms underlying connective action are identified.•Network analysis, modularity analysis and topic modeling were used.•The retweeting network is more centralized in information generation.•The retweeting network however is less centralized in information dissemination.•Issue alignment was identified within and across subcommunities in the network. This study applies the connective action framework and network analysis to analyze how counterpublics used social media to form cliques and mobilize support toward a local issue at the global stage. It presents a case study of the 2019 Hong Kong protest to uncover under what conditions hashtag activism can evolve into connective action. The network approach allows us to examine users and content simultaneously to identify three mechanisms underlying the movement: generative role-taking, hashtag based storytelling, and issue alignment through diverse social groups. Combining descriptive network analysis, modularity analysis, and topic modeling, we demonstrated that hashtag activists during the Hong Kong 2019 protests used different strategies of connective action to engage in information sharing and drive the emergence of connective action. (122 words)