To analyze the relationship between teachers’ freedom and their required pedagogical content knowledge (PCK), I consider emergent curriculum as an extreme end of curricula with a lot of freedom and autonomy for teachers as opposed to a conventional prescribed curriculum in which teachers have less autonomy. In examining teachers’ pedagogical content knowledge from predetermined curriculum toward emergent curriculum, I argue that required PCK is evolving. At the extreme level of teachers’ freedom, some substantially new aspects of PCK are needed. One of the most relevant aspects of pedagogical content knowledge for the emergent curriculum curricular knowledge. In an emergent curriculum, the teacher acts as a curriculum developer as well, because the curriculum is not determined in advance. Curricular knowledge requires teachers to be experts in fields of learning that are not necessary for teachers in other kinds of curriculum. In addition to substantive PCK, teachers of emergent curriculum have to be both philosophers and artists to be qualified enough to make decisions about curricular issues. Manuscript profile