The success of the maverick politician Rodrigo Duterte in the 2016 election is cited as a result of the weaponization of social media—whereby professional, tech-savvy strategists mobilized public opinion through a networked system of disinformation. Yet, there is evidence of grassroots campaign support that emerged via online platforms. Those who have mobilized include Overseas Filipino Workers (OFWs), who have used Facebook groups to rally in support of Duterte. This research looks at the activities of two OFW Facebook groups to understand precisely how and why they organized for Duterte. Employing a dualstage thematic analysis on posts and comments by group members between March 28 – May 9, 2016, three key findings emerged. First, motivations for supporting Duterte varied greatly among users and are far more complex than Duterte’s mandate to crack-down on corruption, crime, and drugs. Second, group behavior deviates from top-heavy explanations of online campaign mobilization, as these groups operated autonomously from Duterte’s official campaign. Finally, these groups were not amorphous and had, as the most active members and organizers, certain intermediaries. These grassroots intermediaries sought to amplify support for Duterte by organizing events, using diversionary tactics, and helping to propagate fake news. These findings suggest that while these groups were operating independently, they were not devoid of influence from Duterte’s official social media campaign.