The concept and practice of design thinking has emerged as a useful methodology for examining/reframing complex problems and creating innovative solutions to these problems. Design thinking has also emerged as a valuable set of 21st-century attributes for 'non-designers'. In response to this emergence, a range of individual design thinking courses have been developed within universities, private training organisations, and within businesses and organisations. While there is a relatively small but growing body of research on strategies for developing design thinking curricula and the teaching of design thinking, there is a lack of specific expertise frameworks that support rigorous curricula design development and evaluation. This paper provides a brief overview of the research, which explored the iterative development, evaluation and optimisation of a design thinking course, over three semesters for first-year university students. Key findings are presented. The paper then presents refined conceptualisations of design thinking (including key design thinking attributes), a model of an experiential learning process for design thinking, and an associated 'novice-to-expert' design thinking expertise framework. The findings of this research will be useful for educators who are interested in teaching design thinking to 'non-design' students, and for the design of innovative and effective design thinking curricula and learning environments, which prepare these students for complex and rapidly evolving future 21st-century workplaces, situations and environments.