With an ultimate goal of characterizing teachers' movement toward understanding the epistemic complexity of generative learning environments, this study refers to adaptive teaching expertise (AdTex) as a developmental teaching capacity observable through a teacher's ability to utilize various resources to address the epistemic complexity of knowledge generation practices. The analysis and discussions centered on how teachers develop and utilize epistemic orientation and understandings of epistemic tools for adaptive teaching, making this study distinct from previous research on AdTex. In particular, this study shows a new way to create systematic profiles of AdTex based on the multiple qualitative data sources, including vignettes, interviews, and reflections collected through a multiple-case study with 24 teachers. The qualitative profile analysis suggests that the development of epistemic resources is closely related to teachers' attention to student ideas, student agency, and a balance between flexibility and productivity regardless of context. The analysis demonstrates that the development of epistemic resources can represent the degree of development of AdTex and provide a rich research pathway for future analysis.