A growing literature describes the effects of health behaviors—physical activity, nutrition, sleep, and recreational screen time—on youth neurocognitive development and mental health. This talk will highlight findings from recent observational studies, experimental studies, and meta-analyses on relationships between health behaviors, brain structure, brain function, cognition, and academic performance in youth. Evidence for neurobiological and psychosocial mediators and moderators will also be considered. We will consider how adults working with childr en and teens (e.g., parents, clinicians, teachers, after-school staff) can utilize health behaviors as a tool in their practice. Lastly, we will review the aims and methods of a novel physical activity intervention focused on at-risk adolescents in underserved and vulnerable communities called “Leaders @ Play”.