The 21st century, known as the “metropolitan century”, saw urban populations exceed half the global populace. By 2035, emerging metropolises, particularly in Asia and Africa, highlight the urgent need for research on urban growth, demographics, and mobility’s role in sustainable development. The objective of this study is to explore the key aspects of mobility essential for sustaining metropolitan regions, with a focus on the case of Greater London. The research aims to understand, through interview analysis and urban theories, how mobility contributes to socio-spatial equity, connectivity, and integrated governance, highlighting the importance of sustainability—such as decarbonization and the promotion of non-motorized transport—in the context of global sustainable development commitments. This research, through a convergent analysis of interviewees’ responses, has identified thirty-one fundamental attributes to enhance our understanding of sustainable mobility. The results indicate that mobility is a key driver for socio-spatial equity, connectivity, and integrated governance within metropolitan regions; it also shows that successful infrastructure work necessarily calls for collaboration between different administrative levels. Finally, the imperative for sustainability in mobility—as exemplified by decarbonization and the encouragement of non-motorized transport—arises as an urgent element in ordering development at the urban scale vis-à-vis global sustainability commitments, such as SDG 11.