Politicians have been criticized for not exploiting the deliberative potential of social media platforms. We complement previous definitions of politicians’ success on social media through the lens of network media logic: Despite the lack of deliberation, some succeed in building large digital followerships, which spread their messages via reactions through the network. Analyzing a data set of personal, structural, and social media characteristics of Swiss politicians, we used path analysis to determine which predict their success on Facebook (n = 63) and Twitter (n = 108). Politicians, who are active in parliament, represent urban regions and receive substantial amounts of traditional media coverage also have larger digital followerships on both platforms. Digital followership in turn influences the average number of digital reactions on Facebook, but not on Twitter. Thus, politicians’ success on social media depends on their personal background, political activity, and media coverage, and also their followership and the platform.