The majority of new HIV infections in the United States are among men who have sex with men (MSM), and African American/Black MSM are especially affected. Employing a grounded theory approach, this study presents qualitative data from 21 African American/Black MSM who participated in a substance use and sexual risk reduction intervention trial (Project ROOM [men Reaching Out to Other Men]) in South Florida. African American/Black MSM from Project ROOM reduced their substance use and sexual risk behaviors at a faster rate than other men in the study. The present study examines how the experiences of participation in Project ROOM influenced the behavior change among African American/Black MSM. In-depth interviews indicate that study assessments enhanced African American/Black men’s mindfulness and self-realization of behaviors leading to behavior modification and changes in social relationships. Furthermore, these findings suggest that interventions tailored to the social environment of HIV transmission and substance use behaviors are key to reducing risk behaviors among this population.