Prominent implementation theories and frameworks articulate characteristics of interventions (e.g., contextual alignment) as important determinants of successful implementation in natural practice settings. Yet, few studies have explored such characteristics in-depth. Research is needed to understand how and why interventions' characteristics can make them more or less implementable in their intended practice settings. Child Welfare Services (CWSs) need evidence-informed academic interventions to help children's current and prospective wellbeing. CWSs are complex implementation contexts that likely need interventions to be highly implementable. This mixed-methods case study explored the implementability of Enhanced Academic Support (EAS), a co-designed common elements-based academic intervention for children and families in CWSs, and how characteristics such as flexibility and contextual alignment influenced its implementability.