This study describes policies and practices implemented in 12 high schools (Quebec, Canada) that more or less effectively leveraged extracurricular activities (ECA) to prevent dropout among vulnerable students. Following an explanatory sequential mixed design, three school profiles (Effective, Ineffective, and Mixed) were derived based on quantitative student-reported data. Qualitative interviews with frontline staff revealed that in Effective schools, ECA had a unique overarching goal: to support school engagement and perseverance among all students, including vulnerable ones. Moreover, in these schools staff had access to sufficient resources—human and material—and implemented inclusive practices. In Ineffective schools, ECA were used as ...