The adaptive reuse of cultural heritage (ARCH) is a sustainable heritage management method based on the principle of the circular economy. In response to the financial challenges ARCH faces in its promotion of the sustainable development of circular cities, this study explores the potential of resident donations as a largely untapped source of funding for ARCH projects and the factors influencing residents’ related intentions and behavior. We used partial least squares structural equation models to extend the original theory of planned behavior (TPB) to include policy perceptions, moral perceptions, and heritage awareness. A survey of 2038 residents in Nara Prefecture revealed that perceived behavioral control, behavioral intentions, and moral perceptions are significant positive predictors of residents' actual donation behaviors. Additionally, policy perception and attitudes toward behavior, along with subjective norms, also positively influence the intention to donate. Notably, heritage awareness significantly facilitates the conversion of intentions into actual behaviors. The extended TPB model proves significantly more effective than the original in predicting donation intentions and behaviors. The findings of this study provide insights for policymakers, encouraging a participative approach in cultural heritage management to achieve a virtuous cycle of cultural heritage conservation, thereby contributing to the advancement of sustainable cities.