The purpose of this study was to examine how a recently arrived male English as a second language (ESL) student’s social interaction processes changed as he moved from the periphery of the mainstream toward its core. Using the notions of From a Perspective of Community of Practice and legitimate peripheral participation proposed by Lave and Wenger (1991), this study described what identities, interactive practices, and interactive resources were available to him in a new milieu. Multiple sources of data were utilized, such as participant observation, fieldnotes, the participant’s conversation activities, interview, and the participant’s journal. The results revealed that his identities, interactive practices, and interactive resources were interrelated because he gradually increased his participation in interactive practices and gained access to a wide range of interactive practices and resources as he moved toward full participation in the mainstream.