This study was conducted to specifically examine the leadership of Principal A, who is appointed as a Y high school's internal-type openly recruited principal and worked for the fourth year, and to discuss its characteristics and meaning. To this end, for about 9 months from February to November 2020. A qualitative case study was conducted through in-depth interviews, participation observation, and collection of related data for four research participants, including Principal A of Y high school, an autonomous public high school located in I Metropolitan City. As a result, Principal A's leadership performance characterized the appearance of “conduct actively”, “grow together”, “set a good example”, “communicate even if hard”, and “overcome the difficulties”. Based on his leadership, he drew characteristics of the principal A's leadership, including “A principal as super-leader”, “teachers' educational ability facilitator”, “Educational community creator through communication”, “democratic decision maker”, and “school manager centered on education demand.” As a result of the analysis, the appearance and characteristics of principal A's leadership were found to have a positive effect in terms of leadership performance in the school management plan submitted by principal A after analyzing Y high school during the internal contest selection process. Based on this, it was suggested that it was necessary to prepare institutional standards and improve principal’s appointment system to cultivate leadership necessary for the principal's job and to cultivate competent principals. This study is meaningful in that high schools, which have not been studied much so far, were used as research sites, and internal contest principals, one of the issues of the principal contest, were selected as research participant.