This study of 179 recently incarcerated male adolescent offenders examined how leaders and followers in juvenile offending differed across offense, demographic, intraindividual, contextual, and social domains, and how leader/follower status affected the association between facility peer misbehavior and youth’s own institutional behavior over the first month of incarceration. Results indicated that leaders were older, more criminally experienced, reported higher levels of contextual risk, yet reported lower feelings of social isolation than followers. For followers, early exposure to facility peer drug sales was especially impactful on their subsequent institutional substance use, while facility peer antisocial behavior was related concurrently to all youth’s institutional antisocial behavior at each week of incarceration. Findings suggest that leaders and followers have distinct correlates and may require differential intervention, and heightened vigilance of facility peer relations is important throughout youth’s transition to juvenile incarceration.