Among existing and anticipated changes in global urbanisation and population growth, the challenge of retrofitting suburbia within sustainable cities needs to be considered. However, given the opposing nature of sustainability and suburbia, this task is not easy. Different approaches have tried to define the theory for achieving sustainable cities, but the nature of suburbia presents issues in densification, as density is perceived to limit the liveability and importantly the private sphere that makes suburbia desirable. To begin addressing sustainability in suburbia, the question of how to densify suburbs while maintaining their liveable quality, needs to be addressed. Focusing on the case of Canberra the paper builds a framework for discussing these questions within analysis of suburb density, behavioural studies and the public private interface. In doing so, it is evident that sustaining suburbia through densification, within the context of sustainable cities, cannot be considered without recognising morphology and the need for, and integration of, the public private interface.