School‐based civic education is increasingly recognized as an effective means for increasing political awareness and participation in American youth. This study examines the Student Voices curriculum, implemented in 22 Philadelphia high schools, to assess program activities that mediate gains in outcomes linked to future political participation (following of politics, political knowledge, and political efficacy). The results indicate that class deliberative discussions, community projects, and informational use of the Internet produce favorable outcomes that build over the course of two semesters. Effects were comparable for both white and nonwhite students.