PurposeThe role of a national sport organization (NSO) is prominent when a country hosts a mega-sporting event since the organization is responsible for athlete preparation and coordinating with other organizations to ensure successful hosting. This research examines the impact of hosting a mega-sporting event on the professionalization of an NSO and its consequences on the sport, using the case of the Korea Ice Hockey Association (KIHA).Design/methodology/approachThe study utilizes a qualitative single-case study approach grounded in an interpretivist perspective. Data for this study included semi-structured interviews with key individuals (n = 16) and archival materials.FindingsThe findings indicate that hosting a mega-sporting event was a strong catalyst for the professionalization of the KIHA. KIHA underwent changes in its organizational structures and processes, human resources and interorganizational linkages, all of which contributed to significant transformations in the sport during the event preparation period.Originality/valueThe study elucidates how hosting can lead to increased professionalization and its subsequent impact on the sport. However, the current case demonstrates that the KIHA overlooked certain impacts of professionalization (e.g. internal conflicts and neglected parts of the sport) that should be enacted in order to further the sport’s development. Therefore, NSOs and event stakeholders must carefully assess their sport’s environment and attributes.