Purpose: Much of the support required to live in the community post-traumatic brain injury (TBI) is provided by informal carers. Understanding the nature of caregiving work is important to better support informal carers. This study explored the work being performed by informal carers, and factors impacting on their capacity to manage the workload.; Method: Participants comprised 21 dyads each consisting of an adult with moderate to severe TBI and a nominated carer. Thematic analysis was done on semi-structured interviews with injured participants and carers during the 12-month period post-discharge from hospital.; Results: Results revealed two main themes and eight subcategories: (1) The nature of informal care: describing informal care management work, (personal assistant work; care provider work; family support work; and emotional self-regulation work), and (2) Mediating factors that impacted people's capacity to manage workload (carer intrinsic factors; injured person characteristics; family circumstances; and changes over time.) Conclusion: Rehabilitation providers supporting people following TBI need to focus on broad family contexts; understand the nature of work being undertaken, and carer capacity to carry out that work; and be aware of the unique and changing circumstances of families to better support informal carers. Implications for rehabilitation Rehabilitation services need to focus on broad family contexts rather than focus on the injured individual in isolation. Understanding the nature of the work being undertaken by informal carers, and their capacity to carry out that work is important when considering supports. Rehabilitation professionals need to consider and respond to the impact that changing circumstances have on the capacity of informal care networks to manage care workload.