In this article I develop what I term chameleon masculinity as a specific form of gendered adaptation of military agency opened up by the post-9/11 shift towards ‘population-centred’ counterinsurgency and stabilisation. A gendered analysis of this carefully cultivated form of military agency is central to revealing some of the concealed embodied dynamics that challenge the hegemony of the traditional combat soldier, and in practice enables this form of war. Drawing on 18 months of anthropological fieldwork, for the most part alongside the UK’s Military Stabilisation Support Group, this research incorporates my auto-ethnography as an officer in the Royal Naval Reserves. Rather than focusing at the level of policy, strategy, and doctrine, I examine how the specialized and masculinized agency of ‘the chameleon’ translates tactically into the body of the British military stabilisation operative, showing how this is developed though intensive pre-deployment training in the UK, and embodied and practised through operational deployment in Afghanistan. This reveals the specific agency of chameleon masculinity and how its potential for inherent violence becomes deceptively ‘hidden in plain sight’.