Detention of irregular migrants awaiting deportation is widely practiced in many countries and has been shown to have profound negative impact on health and well-being of detainees. Detention staff, an integral part of the detention environment, affect and are affected by detainees’ health and well-being. The objective of the study was to explore experiences of staff working at Swedish immigration detention centres. Fifteen semi-structured interviews were conducted with staff in three Swedish detention centres and were analysed using thematic analysis. The results indicate that the main challenge for the staff was to manage the emotional dilemma entailed in working as migration officers and simultaneously fellow human beings whose task was to implement deportation decisions while being expected to provide humane service to detainees. They tried to manage their dilemma by balancing the two roles, but still found it challenging. Among the staff, there was a high perception of fear of physical threat from detainees that made detention a stressful environment. Limited interaction between the staff and detainees was a reason for this. There is thus a need to support detention staff to improve their interaction with detainees in order to decrease their fear, manage their emotional dilemma, and provide better service to detainees. It is important to address staff challenges in order to ensure better health and well-being for both staff and detainees.