PurposeThe purpose of this paper is to posit that a key sustainability tool can help provide a needed guide for the many forms of new curricula for academic, public and professional learning communities. The authors demonstrate that key sustainability competency (KSC) research can highlight and provide an array of learning outcomes that can be back cast to co-design flexible, detailed curriculum, pedagogy, practice and assessment structures. They also briefly outline the connection of KSC to education for sustainability (EfS) to provide the educational basis for designing and facilitating classrooms that contribute directly to the sustainability movement.Design/methodology/approachThis paper is a review of literature with a specific focus on Glasser's (2018b) promising use of the tree as an analogy and metaphor for KSCs.FindingsSome, for example, Glasser and Hirsh (2016) claim significant progress in identifying a KSC framework (Wiek et al., 2011) However, the authors raise concerns about the impasse that the literature has demonstrated because these stand in the way of the co-creation of sustainable societies by adjusting how we learn and interact with the world. The authors argue that we must realize and disrupt the destructive actions that form their usual approach and replace them with sustainable habits (Glasser, 2018a), and this requires the emergence of a new class of sustainability practitioners with the skills, attitudes and dispositions that are consistent with being wise, future-oriented, interdisciplinary and global decision-makers (Biasutti, 2015; Biasutti and Frate, 2016; Corney and Reid, 2007; McNaughton, 2012; Scoullos, 2013).Research limitations/implicationsUsing Glasser’s metaphor, the authors assert a process through which the future sustainability practitioner might shift their values and understanding such that their habits and norms shift to create a new, sustainable way of being. The practitioner might demonstrate the competencies of implementing transformative change, modelling sustainable behaviour and wise decision-making. The competency of “empathy, mindfulness and social learning” implies critical reflection on one’s actions in comparison to their social context. Thus, reflection at this stage (tree branches and fruits) could create transformation that shifts one’s values and commitments (tree roots); the cyclical process could potentially begin again.Practical implicationsAn adaptive and flexible framework of KSC could provide learning benefits by building the capacity for learners to think critically and tackle complex sustainability problems in novel ways (Brown, 2017; Glasser and Hirsh, 2016; Sterling et al., 2017; United Nations Educational, Scientific and Cultural Organization (UNESCO) 2017; Vare and Scott, 2007). Innovation and knowledge generation are possible since the KSC could teach “students how to think, rather than what to think, while letting [them] apply this thinking to real-world sustainability problems” (Wiek and Kay, 2015, p. 29). Through the KSC, people could also learn how to transform knowledge into action in their communities (Sterling et al., 2017, p. 160) and create real-world change. This is important, since unsustainable habits that comprise the “business-as-usual” case must be replaced with life-affirming actions and facilitate a new way of being in the world. After all, “[g]ood ideas with no ideas on how to implement them are wasted ideas” (Scott, 2013, p. 275).Social implicationsThe authors have asserted that the implementation of the KSC could have social benefits because its associated pedagogies aim to actively involve learners in transforming society. The sequence sees the individuals’ reflecting upon and evaluating one’s growth vis-à-vis KSC and promotes the development of learning and other habits that betters ones’ competencies (Rieckmann, 2012). Such reflection and empathy are more likely to be inherent to people who contribute to their own learning about the need to be truly compassionate for each other and the planet (Glasser and Hirsh, 2016). In achieving this level of empathy, it is a relatively simple matter then to understand that technology and policy alone are not adequately able to facilitate large-scale and positive change; unsustainability is a problem created by human action and therefore must be counteracted with theories of and solutions to unsustainable behaviours. Integrating a responsive KSC tool into higher education could help build the capacities, capabilities, competencies and eventually mastery and habits of mind and body that give rise to sustainable well-being societies.Originality/valueThe authors summarize and critique the KSC literature with an eye to creating a flexible and adaptive tool for individuals to chart their own path towards being a sustainability practitioner. The conceptual work herein is the first of its kind, and it will assist program who wish to accentuate contextual factors and individual learning objectives into their design.