This study investigates the role of stakeholder engagement in service ecosystem design through a longitudinal case study of a mobility-as-a-service ecosystem. The study makes three key contributions to the literature on service ecosystem design and stakeholder engagement. First, we conceptualize design-oriented stakeholder engagement (DOSE) as a stakeholder's level of resource investments and expenses in design and non-design processes toward a focal design object. This framework reveals how stakeholders’ varying resource endowments manifest across both design processes (reflexivity and reformation) and non-design processes (reproduction). Second, we identify that stakeholders’ reflexive capabilities manifest in three degrees – focused on self-perceived role, current systemic role, and future systemic role – with those stakeholders who are capable of systemic reflection demonstrating higher voluntary resource investments than those who focused solely on their current roles. Third, we identify role myopia and role uncertainty as barriers that impede higher degrees of reflexivity, explaining differences in stakeholders’ resource investments and engagement levels throughout the design process.