It is now widely acknowledged by many academics, practitioners and policy-makers that working across the boundaries of disciplines, sectors, and institutions is vital if we are to effectively address the challenges of sustainability in practice. Geography has always prided itself in being a discipline that has this way of working in its blood. Indeed in 2014 and 2021, the geography and environmental studies sub-panel for the UK Research Excellence Framework described geography as a ‘post-disciplinary’ subject. This commentary outlines and seeks to continue the conversation regarding the ability of those working within and close to geography to cross the boundaries between disciplines and between research and practice. The paper describes two of author's experiences of working within policy-practice settings where he has brought geographical, environmental and sustainability thinking to bear, aiming to achieve impact. Drawing on previous work exploring the question of disciplinarity in geography and understandings related to models for and effectiveness of the interface between science and policy, this paper offers some suggestions on what might it take to be more effective in working across disciplinary and policy-practice boundaries.