This study was purposed to find the direction of improvement of the principalship by comparing principals' jobs, the process of certification, recruiting, selecting and appointing, and professional development between Korea and USA. The review of literatures, observation and interview methods were adopted for the comparisons between two countries. Major differences between two countries were summarized as five folds: (1) Principal's jobs were declared on the law as School administrative works, Supervision of staffs and Student teaching by in Korea but were based on six ISLLC standards constituted of Facilitating the vision, School culture and instructional program, Managing the organization, Collaboration and community engagement, Ethics and integrity, and Understanding publics as the licensure requirements and assessment for principals in USA, (2) On the one hand Korean principal system was closed promotion one which is selecting candidate principals among teachers, training them with in-service program, and then appointing to principal position, on the other hand USA adopted open-competition one for the selecting and appointing principals among trained and certified candidates from graduate level after Masters degree, (3) professional development opportunities were not enough after appointed as a principal in Korea, but professional development was only survivorship of principalship in USA, and last (4) Principals' weak power was liked by their teachers in Korea but strong leadership was required by the publics in USA. A policy direction for the improvement of principalship was implied in "How can we more professionalize the principalship in Korea?".