Diversity and inclusion (D&I) bring many benefits to society, particularly in public sector organisations servicing increasingly diverse communities. To deliver public value, government agencies at all levels must more intentionally direct public sector knowledge, skills, and experiences to shape the current and future capabilities of a more diverse and inclusive workforce. Fully optimising workplace D&I has proven elusive. An evolving array of new and residual policy and practice elements has led to a mismatch of goals and outcomes. Moreover, many accepted ‘best’ practice approaches are out-of-step with rapidly shifting societal and workforce compositions and mechanisms and societal expectations for organisations to reflect and embrace D&I. Accommodating these shifts demands a bolder, more agile ‘next’ practice approach that is fit-for-purpose in creating and maintaining a modern, diverse, inclusive workplace. This practice-focused article constructs a Capability Maturity Model to guide D&I decision-making and support continuous improvement.