This paper focuses on challenges experienced by 'teacher-FS leaders' implementing Forest School within the neoliberal and risk-averse culture of UK primary school education. Thematic analysis of interviews with 12 'teacher-FS leaders' identified five key themes: embedding Forest School within the curriculum is a long-term process; negotiating the performative culture and curriculum constraints; professional identities, values, and pedagogies; negotiating risk aversion; budget and time constraints. Teacher-FS leaders adapted FS principles to meet the needs of their primary school setting. However, they found ways of overcoming challenges, and sought to persuade others of the value of Forest School and outdoor learning.