EFL learner strategy has become a popular issue since English considered as an International language which goes through with international public communication tools. In this study, the researcher focused on verifying learner strategy in enhancing English mastery inside classroom context of Indonesian college student. This study was qualitative research applied case study approach, which involves grounded theory method. The subject of this study was a learner which was considered as good EFL learner. Findings indicated that: (a) Good EFL learner acts to obey a rule of learners (discipline); (b) Good EFL learner tends to be relaxed and not easily upset (easy going); (c) Good EFL learner has an eager to learn or to know something (curiosity); and (d) Good EFL learner dare to be different or prefers to act differently. In addition, (e) Good EFL learner usually determined to follow a particular plan of action and sometimes using words in a clever and funny way (serious and witty).