BackgroundAutistic children and adolescents have academic performance challenges and are often reluctant to participate in physical activities. Executive function (EF) abilities generally remain stable or worsen as autistic children get older and obesity and lack of physical fitness are frequent concerns experienced by these individuals. Finding ways to address these concerns has the potential to improve outcomes in autistic youth. MethodWe conducted a 12-month, repeated-measures study to examine the effectiveness of a mandatory 35-minute daily school physical activity intervention involving low to moderate exertion for autistic adolescents (n = 29). Changes in fitness, EF, social responsiveness, and restrictive and repetitive behaviors were examined. ResultsSignificant improvements were seen in fitness, EF areas (specifically cognitive flexibility and planning/organizing), restrictive and repetitive behaviors and social responsiveness. ConclusionFindings suggest that participation in a mandatory daily 35-minute physical activity program with low to moderate exertion is feasible and may contribute to improved EF, fitness, restricted and repetitive behavior, and social responsiveness in autistic adolescents.