This paper assesses the significance of social media for the Finns Party and the related anti-immigration movement from 2007 to the present day, in light of theories on the relationship of populism and social media. These include people-centrism, disenfranchisement, homophily, the attention economy, media elitism, and (lack of) communicative resources. Tracing the historical trajectory of the Finnish anti-immigration movement and the Finns Party, I argue that the Finnish case is an example of a movement being born online and using social media to build a political identity and strategically gain influence through a party, eventually transforming it from the inside out—rather than the party strategically using social media for its purposes, as is sometimes assumed in party-centric literature. While acknowledging the continued importance of parties, research on contemporary populist movements must take into account the political engagement of citizens facilitated by online media.