The purpose of this study is to examine the experiences of Lead Teachers(LTs) in charge of Global Citizenship Education(GCED) in schools. In-depth interviews of 10 LTs were conducted for this purpose, utilizing qualitative case study method. Following questions were asked to understand their field experiences in schools: First, how did the teacher develop an interest in GCED? Second, how did they teach GCED in the school, and in doing so what difficulties have they faced? Third, what motivated them to continue teaching GCED in the school? The findings from the study are as follows. First, empirical studies of LTs provide useful insights which close the gap between theoretical/political discourses and actual practices of GCED. Second, the most significant motive by which teachers can continuously practice GCED in the face of numerous difficulties is that they have found educational value and meaning from their work. Third, it is up to the individual teacher’s will and expertise that allow GCED classes to flourish. Therefore GCED should focus on understanding what kind of experiences teachers go through at different grade levels in order to find out the optimum conditions for support.