With the convergence of China’s “entrepreneurial society” and the “digital age,” part-time entrepreneurial behavior (PEB) has received widespread attention as a new form of labor relations and entrepreneurial paths. Entrepreneurial self-efficacy (ESE) is an important indicator of entrepreneurs’ confidence in their skills and in coping with uncertain entrepreneurial challenges. However, studies on how ESE affects different types of PEB have not been thoroughly carried out. To fill the existing research gap, the primary objective of this paper is to thoroughly investigate the individual impact of three key factors, namely organizational management self-efficacy (OMSE), opportunity development self-efficacy (ODSE), and risk-taking self-efficacy (RTSE), on economic profit-driven part-time entrepreneurial behavior (EPEB) and self-value-driven part-time entrepreneurial behavior (SPEB), respectively. Based on the “cognition-environment-behavior” logic of triadic reciprocal determinism, this study also aims to examine the moderating effect of entrepreneurial resources (ERs) and attempt to understand how external factors regulate internal factors (OMSE, ODSE, and RTSE) to form the results of EPEB and SPEB. This study adopted a quantitative research approach with a questionnaire survey, taking 457 part-time entrepreneurs in 11 major cities as subjects. The main results show that (1) OMSE and ODSE have a positive effect on EPEB, while RTSE has an inverted U-shaped effect on it; (2) ODSE and RTSE have a positive effect on SPEB, and OMSE has an inverted U-shaped effect on it; and (3) ERs play a positive moderating role in the above processes. The results can not only effectively guide part-time entrepreneurs in PEB but also provide a reference for the government to improve part-time entrepreneurship policies.