Background: Transitions into informal care roles are associated with various characteristics, for example gender and geographic proximity, but such associations are insufficient to explain role delegation, overlooking the interpersonal structure–agency nexuses that constitute role trajectories. Methods: This paper explores unequal role delegation within 7 families affected by dementia, presenting data from interviews with 7 people with dementia and 26 carers living in the community in the United Kingdom. Findings: Two key care roles are identified: the relatively un‐involved role of peripheral actors and the lynchpin role of main carers who take on most of the care tasks. These roles emerge from negotiations around a range of extraneous factors that collectively comprise cumulative baggage, including historic conflicts and childcare commitments. The unequal distribution of care reflects widely noted demographic associations with role delegation, but is enacted and justified through the interpersonal negotiation of personalised meanings regarding individual circumstances and suitability. Conclusions: Though deeply personal when taken at face value, these meanings imbibe sociocultural norms and political economies of care to structurally position family members in relation to each other and signpost appropriate candidates for caring roles, even before such care is required.