Physical activity (PA) is linked to multiple positive health outcomes for young children, with potential benefits in other domains as well. Engaging in higher intensity PA may produce positive gains for children with autism spectrum disorders (ASD), especially in academic engagement and on-task behavior. However, there is limited research documenting current levels of PA in young children with ASD and effective strategies for early childhood educators to increase PA. The aim of this study is to address these gaps by examining the extent to which embedded antecedent exercise (AE) increases and sustains engagement for children with ASD in early childhood settings. Three kindergarten students with ASD participated in this study, using a single-case withdrawal design to investigate the relationship between intensity of PA and student engagement during two unique classroom activities. Overall, results showed an increase in student engagement across classroom activities after participating in embedded AE.