A mixed-methods study grounded in Renzulli's Operation Houndstooth Intervention Theory examined the impact of different types of volunteer experiences on the six co-cognitive factors (Optimism, Courage, Romance With a Topic/Discipline, Sensitivity to Human Concerns, Physical/Mental Energy, and Vision/Sense of Destiny) associated with the development of social capital in high school students. Results indicated that volunteer experiences, which encourage students' selection of and active involvement with community-based projects, may positively affect Physical/Mental Energy. Also, allowing students face-to-face time with dissimilar volunteer recipients may positively affect Sensitivity to Others. Implications for educators and researchers are discussed.