This qualitative study examines the facilitators and challenges of integrating Experts by Experience (EbyE) activity in mental health services in the public sector from the perspective of mental health professionals and trained EbyE. The research data consist of four focus group interviews conducted in one hospital district in Finland. In the hospital district, EbyE activity is an established working model in mental health services. The professional focus groups had 9, and the EbyE focus groups had 13 participants. The data were analysed using abductive content analysis. The experiences of professionals and EbyE emphasised the successful integration of EbyE activity. The identified facilitators of integration included an organisational culture that values EbyE activity, facilitating operating structures, and extensive implementation and utilization of EbyE activities. Despite successful integration, certain challenges were described with regard to actors and practices. The findings indicate that the hospital district has overcome many of the obstacles to the integration identified in previous studies. The findings highlight the role of effectively implemented, organised EbyE activity.