Public service leaders – senior civil servants who lead and improve major government functions – are at the heart of government effectiveness. They translate political direction into the policies and programmes that keep citizens healthy, safe, and economically productive. In order to do so, however, they need to have both the right skills and institutional support to deploy them effectively. This paper summarises insights from a recently completed project that addressed this challenge. First, the paper identifies four leadership capabilities that are necessary to respond to complex policy challenges: values-based leadership, open inclusion, organisational stewardship, and networked collaboration. Second, the paper outlines a model for assessing senior civil service systems, i.e. the policies, processes and tools needed to develop these capabilities and support leaders in using them. The paper concludes with recommendations to help governments take a systematic approach to the development and management of their public service leaders.