This study examined the relationships among cognitive acceptance, behavioral commitment, psychological need satisfaction, autonomous extrinsic motivation (EM) for physical activity (PA), and PA behavior. Participants (N = 456, M age = 40.7 years) completed online measures of these variables, and data were analyzed using structural equation modeling. Results indicated a direct pathway from behavioral commitment to autonomous EM, plus indirect effects via autonomy, competence, and relatedness. There was no direct pathway from cognitive acceptance to autonomous EM, but there were indirect effects via competence and autonomy satisfaction. There was a direct pathway from cognitive acceptance to self-reported PA plus indirect effects via autonomous EM. There was no direct pathway from behavioral commitment to self-reported PA, but there were indirect effects via autonomous EM. Cognitive acceptance and behavioral commitment potentially support the development of autonomous EM for PA. Future research using longitudinal and intervention-based research designs is required to determine the causal relationships among these variables.