American ESL curriculum, WIDA, introduced in 2004 have been revised twice in 2007 and 2012. The fundamental objective of WIDA is improving academic language fluency in the context of school life and curriculum of certain grade. Therefore, WIDA emphasizes extracting themes, genres, cognitive functions, and socio-cultural contexts of other curricula for ESL educational contents. For this end, WIDA provides educational goals of every grade in elementary and middle school ESL programs while introducing two grade clusters goals in High School programs. Meanwhile, 2012 WIDA elucidates that ESL curriculum should be helpful in preparing college education and job preparation and it can be applied in various forms. This study proposes future directions of KSL curriculum based on the analysis of current status and past evolutionary paths of American ESL curriculum. There is a need to revise grade clusters of KSL system. Contents of KSL texts should be elaborated reflecting fluency criteria of each grade. Consensus should be made regarding how much contents of other curriculum need to be imported KSL curriculum. Guidance for KSL teachers should be provided because they need to have opportunities in mastering theories and practices of contents-based KSL education. Lastly, there is a need for discussion on the way of projecting cultural aspects to KSL contents.