Most of training institutes of public sectors have neither concerned about leadership education and development nor offered enough programs to trainees. Besides the development of programs and curriculum is based on classification of traditional subjects. This leads to the research topic of expanded role of adult and continuing educators and clarification of legitimate needs of the leadership model. The objective of this research is to provide the rationale for leadership education and development for adult continuing educators and researchers in order to enhance the validity and efficiency of training and program development in the public sector. It is expected that continuing educator and researcher should realize the rationale of leadership education and development in public sector for enhancing the validity and relevance of public sector training and human resource development and contributing to the advancement of lifelong education research. This study explored and suggested the logical validity of leadership education and development applied to public sectors based on an investigation of a various topics such as discretion and legitimacy, organizational culture and the like. The major roles of adult and continuing educators were identified to the effect that they should perform holistic human resource developer in public sector, undertaking the role of not only the leadership educator but also the architect and strategist of human resource development, part of which includes inculcation and diffusion of shared leadership culture in public sector.