This study examined the efficacy of mandatory community service to prepare all high school students in a large urban school district for civic engagement. The principal hypothesis asserted that mandatory community service was insufficient in influencing students' civic engagement orientations (CEO) unless accompanied by opportunities for receiving social support. Survey data for this study were collected from all seniors in the district's 17 high schools (N = 1,741) and ordinary least squares was applied in a hierarchical regression in four stages. Findings supported the moderating effect of social support in mandatory service learning especially having a mentor. Students' CEOs, however, were most affected by their perceptions of neighborhood vitality and civic discourse access. Recommendations center on improving the urban district's mandatory community service policy by implementing systems and community partnerships that enable equitable student access to socially supportive community adults and promote deeper integration of service-learning into the broader curriculum. (Contains 9 tables and 1 figure.)