This paper examines a multidimensional set of learning-engagement behaviors by students participating in a community of inquiry. Existing social-inquiry models of learning focus on students achieving shared understanding through solving well-structured problems. These models may not be appropriate for professionally-oriented, graduate online education where students derive distributed and partial understandings of ill-structured, real-world problems. Findings are presented from a study of joint knowledge construction in an online graduate IS management course. Patterns of interactions between learner role behaviors are examined to analyze social engagement in debating course problems. We propose that professionally oriented online courses should frame course problems to reflect students’ cognitive and professional learning goals. Student engagement in learning may be intensified by the early identification and encouragement of thought leaders in various domains of professional knowledge who facilitate and complicate community debate. We examine the implications for online learning environments.