Vietnam has recently witnessed application of leadership development for high school principals in their training programs. These applications have set a few best practices for administrators and school leadership in the context of globalization and international integration in the field of education and training. This study was conducted to investigate how these applications of school leadership development from the point of view of Western authors could be compatible in the context of high school policy and leadership in Vietnam. A mixed method research design (both qualitative and quantitative) was utilized. The sample of the quantitative research comprised 295 high school principals of 5 provinces and cities representing the North, Central, and South regions of Vietnam. The findings of the study demonstrated that training and fostering leadership capacity in stages associated with the career of high school principals helped principals prepare for school leadership, although the level of implementation of this process in practice was still between average and below average. Based on the research results, it is suggested to align theoretical foundations with practices of school leadership. It is also recommended to optimize theories of leadership development for cultivating teaching and administration skills among high school principals in Vietnam. The implications of the study rest in simplifying the complexity of sharing developmental direction as well as allocation of resources at the grassroots level to understand competing priorities and misunderstandings.