Drawing on interviews with and observations of boys enrolled in a bystander violence prevention program at a juvenile detention center, this article provides a sociological case study on how the boys’ biographies and violent lived experiences shaped their engagement with the program. Previous research on bystander prevention programs has typically focused on men enrolled in college who do not have the same kinds of violent histories as the boys in this study do. This article builds upon prior research on prevention programs by demonstrating how at-risk youth participants understand and access the program. We offer suggestions for tailoring bystander prevention programs to more adequately address the specific needs of these populations.