Successful engagement with linguistic, cultural and technological diversity is fundamental for learning and teaching in a twenty-first century knowledge society and globalised economy. In the field of pre-service teacher education in Australia, learning diversity is manifested in and through not only the life trajectories of adults-as-learners, but also the organisational conditions under which they choose to become teachers. This paper examines the dimensions of difference impacting on the design of a university course in literacy and numeracy for people intending to teach in diverse education sectors (primary, secondary, vocational and technical); and systems (public and private schools, colleges, workplace and industry training sites). These adults come from diverse socio-economic and cultural backgrounds, with varying educational, work and life experiences. A theoretically informed conceptual framework is then developed to position learners and learning diversity at the centre of course design. The utility of this conceptualisation to engage with the complex connections of meaning about literacy and numeracy among diverse learning communities is also explored. Significant implications for capacity building of pre-service teachers as future knowledge workers are then proposed.