This study focused on the practical knowledge of teachers educating students with migrant backgrounds, considering changes in the school environment and educational practices in a multicultural society. Since teachers are the first to detect and respond to the changing social environment and demands through students in the school, the practical knowledge that teachers form while solving the problems they face can suggest what educational approaches are needed in our society now. In this study, the practical knowledge of teachers is explored through continuous discussions with teachers educating North Korean migrant students. The teachers participating in the study were trying to practice education in the most appropriate way by adjusting their teachers’ images in a specific context. And in the process, it was recognized that in order to teach students well, it was necessary to understand the backgrounds surrounding them. The teachers were also aware that teachers’ interests were not limited to the school, but that it was necessary to expand them to a wider range in order to understand the social, economic, and cultural backgrounds of the students. This knowledge, which is formed through discussions and reflections in the teaching practice and in the research community, provides important implications for the education of students with migrant backgrounds and teacher education in a multicultural society.