The purpose of this study is to empirically explore the writing trajectory of what and how adolescent writers write and grow. For this purpose, the writing experience of five high school students was analyzed through a semantic network. As a result of the study, first, it was confirmed that what and how adolescent writers engage in writing practices in their life cycle. Second, by tracing the trajectories of adolescent writers’ writing practices, this study describe the aspects of how adolescent writers develop, repurpose, and reorganize writing practice. Third, this study is a case study of a specific adolescent group, examining the characteristics of writing practice and suggesting educational implications. This study is meaningful in that it explored the cases of what writing trajectories Korean adolescent writers form and develop.