Founded in 1969, the National Museum of Modern and Contemporary Art, Korea (MMCA) was transformed into an executive agency in 2006 and became the subject of performance management. The purpose of this study is to understand the historical and contextual background of performance management reform in South Korea and its application to MMCA, and also to analyze the mechanism of performance evaluation and its consequence on the management of a national art museum. For the analysis, MMCA’s annual reports, performance evaluation records, public announcements and proposed schemes of previous directors, and other related news, articles and available information from 2007 to 2017 were collated, and the changes in performance evaluation measures (by index weight) were chronologically compared, reorganized and interpreted in regard to the internal situation of the museum and its directorship. The main finding was that overtime performance index weight in the evaluation result shows a growing emphasis on the directorship term related, urgent and more quantifiable performance goals, which are in support of the further reform of MMCA as a corporate entity. Also, the changes in evaluation composition signal a trend that the most prioritized task of each directorship term differed, and this ultimately caused less quantifiable performances, such as art collection and research related tasks, to weaken in emphasis as part of the performance. In conclusion, the performance management of MMCA from 2007 to 2017 had a beneficial side in promoting the result-based performance specifically and had functioned as a governing tool that effectively engaged and pressured certain urgent tasks to completion, but it also had a weakness in keeping the long term stability of directorship and provoking the continuous development of all parts of art related core competency. The consequence of performance management can be argued as limiting the understanding/evaluation of directorship competency to the achievements that are distinguished and identifiable, therefore the result is difficult to argue for its justification and sufficiency as a representable score of the art museum performance.