This chapter debates how the healthcare workforce is led and utilised, and how connecting workforce planning with an understanding of human factors and workforce engagement can go beyond traditional supply-side initiatives. Workforce planning and development rely on metrics around demand and supply, and whilst there is clearly a material basis for this—marrying assumptions around demand and capacity, knowledge around demographics and disease prevalence—it can also be reductive, conceptualising the workforce as fixed, commodified units. In any healthcare system, increasing numbers without re-evaluating how workforces are organised and led is unlikely to achieve change. Focusing on the NHS in England, this chapter uses existing research to critique current practice in workforce planning through two lenses. Firstly, how ‘planning by numbers’ chafes against policy priorities of integration and increased productivity. Our second focus is on the disjointed relationship between traditional workforce planning and the broader value questions of how complex healthcare workforces are led, and for whom they exist. We propose a model which integrates planning with key delivery priorities, contending that greater integration of the technicalities of planning with organisational and professional development is necessary if we are to be able to impact significant and lasting system change.