This study focuses on employees’ collective engagement (CE) in knowledge-based service firms. CE is a climate-related construct that refers to how employees collectively express themselves psychically, cognitively, and emotionally in their work role. Moreover, the study explores the consequences of CE, specifically, these that are linked to relationship learning (RL) in intrafirm professional service teams (IPSTs), employee commitment (EC), firms’ innovative capability (FIC), and customers’ creative strategy generation (CCSG). The suggested conceptual model was tested in a survey. All survey participants were employed in consultancy firms and represent the population of employees within the domain of knowledge-based service firms. The findings give support to the conceptual model of consequences of CE. Specifically, the findings reveal that CE plays an imperative role especially for EC and RL in IPSTs. This study contributes to deepen and extend research on employee engagement, which is a relatively new concept. Specifically, the study contributes to reveal how CE is linked to several outcomes critical for service firms. No previous research has examined these aspects. Therefore, this unique study enriches our understanding of knowledge-based service firms with the finding that CE is a key factor to orchestrate successfully to trigger RL in IPSTs, strengthen EC, generate customers’ creative strategies in their service offerings, and boost the knowledge-based service firms’ overall capability to innovate.