Drivers for biodiversity loss are largely regulated by policies in non-environmental sectors. The limited mainstreaming of biodiversity into respective policies remains yet to be analysed. During the process of updating the German National Biodiversity Strategy, we conducted 33 interviews and a stakeholder workshop to analyse barriers and levers for biodiversity integration in five policy sectors: agriculture, forests, marine & coastal areas, business & industries, rural & urban development. Based on Biodiversity Policy Integration literature, we distinguish four leverage points for transformation related to inclusive, integrated, accountable and adaptive governance. We found that biodiversity inclusive narratives and innovative approaches exist but are overshadowed by conflicting vested interests. Dominant sector policies are incoherent and continue to provide harmful subsidies. Institutional structures fail to reflexively respond to ambitious agendas and are locked into sector specific accountability hierarchies. Thus, transformative national planning needs to overcome institutional lock-ins and empower agents to develop innovative solutions. •BPI analyses reveal levers for overcoming barriers to effective implementation.•Inclusion of different views and existing practices creates ownership and legitimacy.•Integrated policies must prioritise biodiversity while phasing out harmful subsidies.•Accountability requires collaboration and responsibility across sectors and levels.•Adaptiveness requires reflexive institutions that can react to evaluation processes.