PurposeProcess facilitation as part of a complex intervention for changing or improving practices within workplaces is becoming a common work method. The aim of this study was to investigate what characterizes the process-facilitating role in a complex intervention.Design/methodology/approachThe present study focuses on a complex work environment intervention targeting eight organizational units (workplaces) in the Swedish healthcare sector. The study applies a mixed-method approach and has been carried out in two steps. First, a qualitative process evaluation was performed. Secondly, an evaluation was conducted to see to what extent these identified conditions and mechanisms affected the quantitative intervention effect in term of sickness absence.FindingsThe analysis shows that the facilitating role consisted of three overlapping and partially iterative phases. These phases involved different activities for the facilitating role. Depending on how the facilitating role and the intervention were designed, various supporting conditions were found to significantly affect the outcome of the intervention measured as the total sickness absence.Research limitations/implicationsIt is concluded that the facilitation is not static or fixed during the change process. Instead, the facilitation role develops and emerges through the process of support during the different implementation phases.Practical implicationsThe facilitative role of performing support is based on a combination of support role activities and expert role activities. The support role focuses on support activities, while the expert role includes capacity building through knowledge- and legitimacy-oriented activities.Originality/valueThis study contributes to earlier research by developing a methodological approach for carrying out process facilitation in complex interventions.