This paper focuses on enacted PCK (ePCK), i.e., the specific knowledge and skills that science teachers use in their practice, as it plays out in specific classroom contexts while teaching particular content to their students. In unpacking this aspect of the Refined Consensus Model (RCM) of PCK, we consider both the nature of ePCK and its interactions with other realms of PCK, primarily personal PCK (pPCK). Recognising the complexity of practice—in terms of both the uniqueness of each classroom situation and the necessarily spontaneous nature of classroom interactions—we propose a mechanism through which pPCK is transformed into ePCK, and vice versa, throughout the plan-teach-reflect cycle. We then illustrate these ideas using several empirical examples of efforts to capture and analyse science teachers’ ePCK (and associated pPCK). We conclude with discussion of some of the opportunities, challenges, and implications of using the RCM, along with our unpacking of ePCK and its relationship to pPCK, as a means of understanding the knowledge that science teachers utilise in the midst of planning, teaching, and reflecting.