Background and Context: Using a transformative learning framework, this qualitative study examines the perspectives and practices of 70 middle and high school content area teachers who attended two or more summer professional development workshops. Objective: This study describes how teachers' disciplinary perspectives and backgrounds influence their understanding of CT infusion and their implementation of CT-infused lessons. Method: Data sources for this qualitative comparative case study analysis included: retrospective video reflections, implementation surveys, post-PD surveys, and instructional materials. Findings: Analysis revealed differences in terms of disorienting dilemmas teachers faced, shifts in their frames of reference, the form of classroom CT infusion, and their integration of specific CT concepts. Implications: This study contributes a comparative analysis of how teachers from different content areas come to understand CT infusion and implement CT-infused pedagogical practices to support their disciplinary teaching. Findings indicate the importance of including all teachers, STEM and non-STEM, in CT infusion efforts.