Content-based instruction (CBI) has been touted as an effective curricular approach in a wide range of educational contexts, including immersion and English as a second language. Yet this approach to curriculum design is rarely implemented in conventional K-16 foreign language (FL) programs in the United States today. The phenomenological study described here attempted to gain a deeper understanding of factors affecting the implementation of CBI by exploring three traditional FL teachers' learning experiences during a year-long professional-development program designed to introduce the approach. Transitioning toward CBI, the findings suggest, can be a professionally intimidating experience, involving a struggle to re-examine one's own teaching identity and one's vision of what teaching and learning ought to be. Important implications emerging from this study include a need for professional-development programs to better scaffold teachers' learning experience and to create safer environments for teachers to explore pedagogical alternatives.