This article examines how the Biden administration sought to legitimate the wide-ranging chip export controls on China (introduced on 7 October 2022) and to convince allies to adopt similar measures. Grounded in a qualitative analysis of US official documents, this study not only draws out the overarching rationale advanced by US officials: China’s unregulated access to advanced chips constitutes a major threat to the US and allied security. More importantly, leveraging insights from frame alignment, it uncovers the underlying patterns and dynamics of the legitimation-cum-securitization process. Substantively, US officials insisted on viewing US technological leadership and the escalation of export controls through the security lens, associated China’s (mis)use of advanced chips with the erosion of US technological supremacy, military security and national security at large, and framed blocking China’s access to advanced chips as critical for the security of the US and allies. This analysis offers broad insights into the contestation and legitimation of an increasingly common yet potentially pernicious phenomenon in US-China relations: enacting techno-economic sanctions in the name of national security.