Pain acceptance is a robust predictor of adjustment to chronic pain; however, the dynamics of pain acceptance in daily life are largely unexamined. Furthermore, research on pain acceptance in those with pain and physical disability is needed. To examine pain acceptance in daily life, we collected 7 days of ecological momentary assessments of pain intensity and pain interference (5 times per day) with continuous accelerometry (physical activity) in 128 individuals with chronic pain and spinal cord injury. Multilevel modeling revealed that pain acceptance significantly moderated the momentary association between pain intensity and pain interference; those with higher pain acceptance experienced a blunted increase in interference when pain was high. Pain acceptance also moderated the association between pain intensity and physical activity; high pain acceptance was associated with an increase and low pain acceptance with a decrease in physical activity in the context of high pain. The activities engagement component of pain acceptance was a slightly more robust driver of these interaction effects; whereas activities engagement significantly moderated the association between momentary pain and pain interference as well as physical activity, pain willingness exerted a significant moderating effect on the momentary association between pain intensity and pain interference only. These findings suggest that both components contribute to the decoupling effects of pain acceptance. Task persistence did not show the same moderating effects, indicating that pain acceptance may be unique from other types of behavioral pain coping in its ability to decouple expected associations between pain intensity, pain interference, and physical activity.