The purpose of this study was to explore, by employing the Delphi method, key indicators and factors for establishing sustainable conventions and exhibitions (C&E) events in a destination in lieu of holding one-off events. In addition, the identified factors for establishing sustainable C&E events were assessed using the analytic hierarchy process (AHP) with a multi-group approach. First, internal and external factors that impact continuous hosting of C&E events in a destination were identified in previous research and reviewed. Second, three stages of Delphi surveys were conducted with three groups of experts in the C&E industry (academic scholars, industry experts, and government agencies in Korea). Third, data were analyzed from 35 and 29 participants in the first and second Delphi rounds, respectively, as well as from 17 panelists in the subsequent AHP analysis. A total of 33 indicators were developed and categorized into five factors for continuity of regional C&E efforts: event contents and capabilities, organizers and support/sponsorship, impacts, facilities in venues and destinations, and the local event environment. Furthermore, all three participant groups reached agreement in rating event contents and capabilities as the most important factor, with the local event environment as the second most important factor in achieving sustainable regional C&E. However, the opinion of government agencies for the third and fourth most important factors differed from that of the other two groups. The current study contributes to the understanding of the under-investigated area of sustainable C&E. Based on these findings, host destinations can establish innovative strategies for sustaining C&E as a long-lasting legacy.