This study delves into the intricate dynamics of controversial issues in environmental education, challenging conventional notions. It explores the relationship between "controversy" and the field of environmental education, elucidating its multifaceted dimensions in and ambitions of teaching practice. In dialogue with previous research and based on our empirical study, we contend that controversy's existence transcends the mere content of education and extends to its perceived fundamental core and normative underpinnings. We argue that controversy, including controversial sustainability issues (CSIs), is not confined to educational content alone but encompasses the purposes of education. We propose that controversy in educational encounters cannot be neatly categorized as a fixed, predictable social product and is not solely dependent on student interaction. This challenges earlier research positions that linked controversy to the presence of debate or dissensus in a subject area. Our study challenges the traditional understanding of controversy, highlighting its partial spontaneity and unpredictability in teaching. This contrasts previous positions that emphasized the epistemic dimension of controversy. Instead, our findings suggest that controversy plays an active role in the process of self-formation or subjectification in relation to any content.