Higher education (HE) has a key role in educating graduates as decision makers and change agents; however, sustainability education (SE) remains on the fringes of mainstream curricula and conducted on an ad hoc basis. The context of this research is five connected studies that aimed to investigate the influence of SE on tertiary students’ views, knowledge, behaviour, and agency to contribute to sustainability transitions. The mixed-methods study investigated learning for sustainability by focusing on key elements of the “learning system”, namely the learner’s personal context, the teaching context (SE compared to regular education) and learning outcomes. The research was guided by a unique conceptual framework that linked theories in education and learning, environmental psychology, and sustainability transitions. The influence of educational interventions was assessed using online pre-post surveys that consisted of well-established instruments and open-ended questions. Key transversal findings are resistance to SE, converging views and attitudes towards an “anthropocentric environmentalist” perspective, limited empowerment and occasional disempowerment from SE, a focus on personal behaviour change rather than professional action/agency, and limited incidence of wider agency. Cumulative and deeper learning for sustainability occurred with repetition of SE and a greater connection to a student’s lifeworld. The current ad hoc approach to SE in HE is ineffective in creating widespread agents for change. Influences that foster transformative learning for sustainability and the development of competency and agency for sustainability are identified, and recommendations are provided for educational policy and praxis to enhance student learning and agency for sustainability transitions.