While studies on the teaching of English for specific purposes (ESP) in higher institutions have been widely explored, there is a paucity of research addressing how ESP teachers in higher education deal with their emotional geography when teaching ESP. The data of this present study were garnered through in-depth interviews and analyzed following Braun and Clarke’s (2014) thematic analysis. Anchored by Hargreaves' (2001) emotional geography, the study revealed that the participant had undergone negotiated emotional changes in his experiences as an ESP teacher, which were anchored by physical, social, moral, professional, and political aspects. The findings of this study informed that the participant experienced sustainable adaptation through negotiated emotional changes in his role as an ESP teacher in tertiary education. Furthermore, the present study revealed that ESP lecturer shows five aspects of emotional geographies. Understanding the results of the current study may encourage ESP teachers to handle their feelings when instructing with caution. The participant's stories in this study provide pedagogical insights for redesigning curriculum that focus on ESP learning. Policymakers could also use the results of this study to implement training programs for ESP teachers on how to successfully teach English for specific purposes for non-English department students.