Purpose In online courses, asynchronous discussions are a common course activity that helps build community, explore concepts and provide an opportunity for formative feedback. Design/methodology/approach This case study explored engagement patterns in the Yellowdig platform used in an introductory-level chemistry class. Data were examined using Z scores, multiple regression, ANOVA and non-parametric testing to identify the impact of student activity on discussion and summative assignment grades. Findings Profiles of learner engagement were identified using the interactive, constructive, active and passive (ICAP) cognitive engagement framework. These profiles can be used as predictors of student performance. Moderately high and moderately low activity groups scored significantly better than low or significantly low activity groups. Originality/value This study unveils distinct learner engagement profiles linked to performance outcomes, providing valuable insights for online course design and pedagogical practice.