In this article, sustainability education is defined within the three orders of change--education "about", "for", and "as" sustainability. The third-order change, education "as" sustainability is defined as transformative sustainability education--an ontological change in how humans and the material world relate. The dominant higher educational paradigm tends to educate "about" subject matter (i.e., sustainability) distanced from material and focuses on individual human cognition. This does not go far enough to enact sustainable change. Rather, a human and nonhuman materialization within teaching and learning is explained through agential realism, as conceptualized by Barad. The author narrates her way through her own transformative learning journey as an environmental science and sustainability educator going from a reductionist paradigm instructor into a relationality paradigm educator living into sustainability. From dualist teaching in environmental and human health where the study of food was an object, she undertook teaching and research on the pedagogy of food as a material subject. The findings explore the practice of agential realism in relation to the field of transformative sustainability education, namely, that teaching and learning intra-actively engages body, mind, and all material, including food, water, soil, trees, people, and communities. This is a profoundly transformative pedagogic shift in higher education. Whether we teach sustainability-related subject matter or not, a relational ontology of teaching and learning has the potential to create the conditions for a transformative learning process through an iterative reconfiguring of our relationality--moving towards a social and ecologically sustainable society.