Cities around the world are recognising the need for innovative solutions to address the growing chronic disease burden in the context of urban population growth. In this chapter, we propose transitioning from monocentric to polycentric city models as a solution to this contemporary challenge, particularly in the context of Australia. Such transitions will bring fundamental changes to the way people move across the city: from car dependency to active mobility. Essential features of the polycentric city for enhancing population health include improving walkability and bikeability, reducing driveability, promoting public transport use, and integrating greenspaces. We discuss the importance of some key aspects of urban planning and public-health research for providing a strong evidence base to guide the implementation of the polycentric transition, including identifying specific thresholds for planning attributes that are optimal for population health and understanding community preferences for attributes of polycentric urban forms.