The purpose of this study is to understand the meaning of collaborative design and practice of social studies lesson through teacher learning community. Particularly, by reflecting on the design and practice of international politics lesson- involving politically sensitive issues- through collaboration of social studies teachers, this study aims for a deeper understanding of the significance of participation in teacher learning community. For this purpose, the researcher conducted a self-study based on an international politics lesson taught in 2023 on the topic of ‘conflicts between countries in korea’. The process of collaborative lesson design and lesson practice is a core process of self-study, and is significant in that it is a joint work based on the collaborative foundation of a teacher learning community. The results of the study categorizes the experience of collaborative lesson design and practice through teacher learning community into three areas: sharing and clarifying the teacher's instructional intentions, generating lesson ideas based on fellow teachers’ instructional experiences, and concretizing and practicing the lesson. These experiences carry the following meanings: gaining momentum for action in a ‘safe space’, continuing practice through experiences of solidarity, and becoming gardeners of the social studies classroom ecosystem. For the researcher, teacher learning community provided substantial support to overcome the challenges of classroom practice. The professional act of designing and practicing lesson formed a meaningful educational practice that fostered solidarity as a social studies teacher. Furthermore, in the process of becoming such a gardener, the researcher developed a sense of responsibility as a ‘contextual expert’ for creating a classroom environment where controversial topics can be safely explored.