Feedback drives creativity, yet how individuals benefit from it remains unclear. This study explored the cognitive and neural mechanisms through which interpersonal feedback promotes creativity. The fNIRS measured interpersonal neural synchronization (INS) during feedback, focusing on the prefrontal cortex and the right temporoparietal area. Participants completed creativity tasks (acquisition/transfer) across four groups: interpersonal feedback, one-way feedback, irrelevant communication, and no feedback. Feedback uptake (ignore, copy, and apply) was coded by linking dialogue content to posttest performance, reflecting cognitive processes. Results showed that only interpersonal feedback improved creativity acquisition and transfer. Applying feedback positively correlated with creativity enhancement, while ignoring it was negatively correlated. Notably, interpersonal feedback induced increased INS at the superior frontal gyrus and inferior parietal cortex, which correlated with creativity enhancement and was further amplified when feedback was applied. The study reveals how interpersonal feedback promotes creativity through underlying cognitive and neural mechanisms, offering insights into fostering creativity.