This article rethinks ‘the global’ by analysing the emergence and growth of the Global Counterterrorism Forum (GCTF), an informal platform of multilateral counterterrorism co-operation which has been instrumental in the making of post-9/11 global security law and governance. It problematises and empirically analyses how global scale is enacted through the socio-material practices of translation and assemblage that have been deployed in the construction, maintenance and extension of the GCTF governance network. Drawing from interviews with policy experts and GCTF members, and from participant-observation in GCTF and UN events, the article contributes to the theme of the Special Issue and wider legal debates about the spatiotemporal dynamics of global law and governance by critically analysing how global scale is fabricated in practice and unpacking the politics of GCTF’s global scale-making processes. Focusing on specific techniques and norm-creation processes of the GCTF, like watch-listing toolkits and ‘good-practice’ documents on foreign terrorist fighters (FTFs) and countering violent extremism (CVE), the article analyses how translation, problematisation and enrolment practices have assembled the GCTF as an ‘apolitical’ global security governance body. Our approach opens novel possibilities for socio-legal research on the politics of scale-making and critiquing global security power in action through empirical attention to its assemblage practices.