This study seeks to illuminate the competencies of nurse teachers (NTs) and their operationalization in the context of clinical placement by exploring the challenges of being an NT, as experienced and articulated by diverse groups of interacting agents: NTs, mentors, and students. To gain insight into this area, we employed an interpretative qualitative approach, and applied data source and methodology triangulation: Focus group discussions with nurse mentors and students and e-mail interviews with NTs responsible for the placement learning were performed. Five main themes were revealed: NTs' personal and professional mastery, mastery of student support, mastery of mentor support, mastery of learning/teaching environment, and mastery of conditions while in the clinical placement. In addition, NTs emerged as coordinators, mediators, and moderators of a complex system. Within this system, the complex interplay of diverse components can have various facilitating or obstructing effects. Considering this complexity, we argue that part of those effects is directly connected to individual NTs' characteristics, combination of professional competencies, and application of these competencies in specific situations. We also propose that institutional and departmental contexts, as well as professional contexts of nursing practice and education, influence both teachers and students. Our research draws attention to the further development of organized and structured cooperation within and across institutions in establishing and maintaining links among different contexts of nursing education. With regard to placement learning, the complementary competencies of NTs and mentors, which mesh across fields and domains of expertise, appear to be a possible solution.