Inclusive food value chain development is particularly challenging when numerous smallholders engage in production and trade of non-standardised food products within spatially dispersed systems. Drawing on the concept of human activity systems with an emphasis on purposefulness, we provide a situated account of the activities and relations that shape the pineapple value chain in Uganda. Based on semi-structured interviews with farmers, brokers and traders, we examined the creation and maintenance of business relationships as well as challenges faced. Findings show how trust unfolds to mediate exchange relations that structure chain organisation. Reflecting the uncertain business environment and vulnerability of actors, trustful relationships are simultaneously threatened by opportunities for short-term gain, referred to as “cheating”. Embracing the importance of trust-based relational exchanges for sustaining local economic systems can provide critical leverage for development that puts smallholder farmers and other small-scale value chain actors at the centre.