Intercultural language teaching and learning has increasingly been adopted in state school systems, yet studies have shown that language teachers struggle to include it in their practice. The aim of this study is to use dynamic systems theory to examine how a German as a foreign language teacher in a New Zealand secondary school adopted a project designed to promote intercultural communicative language teaching. It does this with data from a microgenetic analysis of a session in which the teacher was introduced to the project and a qualitatively analyzed interview in which the teacher reported her beliefs and practices for teaching culture. The findings show that the teacher adopted the project by conceptualizing it through the practical challenges involved in using it as a formal assessment. In an interview, she expressed her beliefs about culture in language teaching, and there was some evidence that they reflected the process of adopting the project to be an assessment. The implications focus on the project as a basis for further development of intercultural teaching.