Shared e-scooters in South Korea accommodate urban short-distance travel demand and enhance public transport accessibility. However, facing rising accidents and regulatory uncertainty, a legal and institutional framework capable of simultaneously guaranteeing safety and industrial sustainability is imperative. To identify policy priorities for a sustainable shared e-scooter ecosystem, this study constructed a hierarchical model comprising three upper-level and twelve lower-level factors based on expert consultation and analyzed their relative importance using the Analytic Hierarchy Process (AHP). The results indicated that among the upper-level factors, the “User” dimension carried the highest weight, followed by the “Government” and “Operators.” For the lower-level factors, “Clarification of traffic rules” was identified as the highest priority, with “Transition to a registration and licensing system” and “Clarification of the responsible ministry/agency” ranked subsequently. Furthermore, a comparative analysis between private and public sector experts revealed distinct perceptions: the former prioritized “Deregulation of mandatory helmet use,” whereas the latter emphasized “Clarification of usage safety standards.” Nonetheless, given the consensus across both groups on the critical importance of “Clarifying traffic rules,” this factor should be regarded as a prerequisite for policy formulation. Moreover, the findings imply that it is essential to establish an institutional foundation for systematic market management by enhancing operator accountability through a “Transition to a registration and licensing system,” and to ensure policy consistency by “Clarifying the responsible ministry/agency.”