Abstract
This study aimed to investigate factors attributable to English teacher professional becoming and how the factors have shaped their professionalism. The subjects of the study, called informants, were six English teachers from upper secondary level of education (Sekolah Menengah Atas (SMA) and Madrasah Aliyah (MA)) in three different regions in Indonesia: Malang, Mataram, and Lombok Barat. The research design was constructivist grounded theory. Findings of the study reveal that, prior to their teaching induction, early interests in English and high aptitude are two contributing factors. After the induction, their professional becoming is influenced by level of job satisfaction, commitment to their own and student learning, communication skills and resilience. Recommendations to obtain potential professional teachers of EFL and strategies to help them develop and maintain their professionalism are also discussed