Instructors' discussion design and facilitation have critical influences on online learning community development. Emerging network analysis methods were used to examine the development of an online learning community within a graduate-level course, the variations of an experienced instructor's discussion design, and the dynamics of her discussion facilitation. Results indicated that students gradually formed an interactive online learning community. The instructor, overall, played a facilitator role in this community; yet her participatory roles varied within different discussions during different time frames. Her participatory role evolved from a guide in the first class discussion, to varying roles, i.e., a facilitator, an observer, and a collaborator within different group discussions at the middle stages of the course, and to an observer in the course's later stages. Methodological implications for using social network analysis in online learning community research, and practical implications for designing and facilitating discussions that foster online learning communities were proposed. •Emerging social network analysis methods were used to examine the development process of an online learning community.•Students formed an interactive and cohesive online learning community over time in discussions.•The instructor's participatory roles varied in class and group discussions at different time frames during the course.•Methodological implications for using social network analysis methods in online learning community research were proposed.•Practical implications for designing and facilitating discussions that can foster online learning communities were proposed.