Previous studies have shown that social media is effective in large-scale mobilization, facilitating leaderless and more flexible forms of resistance. However, some scholars argue that this type of mobilization suffers from a lack of organizational form and collective identity. This paper shows that social media-centered networks can in fact promote collective actions powerful enough to challenge a corrupt president. We also prove the role of emotions in collective actions. Using an empirical analysis of the 2016 Presidential Impeachment Protests surrounding “Choi Soon-sil Gate/’ we first demonstrate the effects of social media activities on participation in collective actions. Next, we explore the effects of anger on social media activities and participation. In short, this study reveals a new angle on social media’s influence in mobilizing collective actions by analyzing the effect of emotions on participation. In this process, social media activities are escalated by emotional outbreaks, and participation then increases throughout a given collective action.