This paper analyses the impact of an evaluation-focused language teacher education program under Vietnam's National Foreign Languages 2020 project, run at Hanoi University in 2015 and 2017. Funded by The Ministry of Education and Training (MOET), this intensive 150-hour university-level program employed international experts to deliver content about evaluation. The pedagogical goal was to enhance the capacity of 'key' teachers by guiding their application of theory-informed strategies to their institution's curricula and teaching materials. The underlying policy-directed goal was alignment with the "Circular on Issuance of the 6-level Foreign Language Proficiency Framework of Vietnam" (MOET, 2014), the "Vietnamese Foreign Language Proficiency Framework" ("VFLF"). This study outlines the needs the course met under national policy, demonstrates how these were achieved and describes the course's impacts and constraints. A naturalistic interpretative enquiry, it draws on questionnaire data from participants to assess how the program met its objectives and the degree to which participating language teachers reported applying its content to their practice. The study points to a gap between the aspirational rhetoric of the 6-level framework and the constraints posed by gatekeepers where the 'key' teachers are supposedly present and future leaders but often lack the autonomy to innovate.