Background The built environment can influence mental, physical and planetary health. For example, walking and cycling infrastructure can increase physical activity and reduce associated risk of disease; green spaces can support mental health and biodiversity; insulated homes are resilient to overheating and reduce energy use, affecting fuel poverty and climate change. Design decisions consider many factors in a complex urban development system, beyond health concerns. These include political, commercial and technical issues, involving multiple stakeholders from public, private and third sector organisations. We sought to understand the complex system of urban development decision-making to identify leverage points for interventions to support healthier place-making.

Methods Semi-structured interviews with 132 multi-sectoral stakeholders were conducted to understand how health is considered in urban development. Participants were professionals spanning property development, urban and transport planning, real estate, finance, sustainability, public health, and elected representatives. Purposive sampling was informed by stakeholder mapping and snowballing, targeting individuals with expertise and/or influence in urban development decision-making in England. Topic guides covered: actors, institutions and networks; perceptions of why healthy places are not delivered; and decision-making processes, including using evidence. Questions also covered community involvement, health economic valuation and legal considerations. Researchers from nine diverse disciplines collaboratively conducted the interviews and coded interview transcripts, using deductive and inductive codes, and wrote discipline-specific summaries. Thematic analysis was conducted, informed by meta-ethnography.

Results Three themes were developed: ‘competing priorities’, highlighting trade-offs for key groups (national government, local government, private sector property developers); ‘getting around the ‘rules’’, considering how policies and legislation may insufficiently control development and meaningful community engagement; and ‘justifying a focus on health’, highlighting the need for greater clarity about what makes development ‘healthy’ to demonstrate responsibilities and increase funding. Taking a systems perspective, the findings develop a socio-ecological model that identifies challenges and potential leverage points at three levels: individual motivations; organisational priorities; and structural factors.

Conclusion A multi-faceted approach is required to tackle challenges of creating healthy places in the complex system of urban development. These must span multiple levels and may interact. Interventions could include targeting behavioural norms; integrating health into policies; and greater clarity and consensus around definitions of ‘healthy’ urban development. This could increase demand for healthier place-making, justify it as an organisational priority and integrate health within structural control mechanisms.

The themes were developed by an embedded researcher working part-time in local government. Researchers with other experiences and knowledge may have interpreted the data differently.