This paper examines the value of participatory approaches within interventions aimed at promoting mental health and wellbeing in the workplace. Specifically the paper explores data from the thematic evaluation of the Mental Health and Employment project strand within the Altogether Better programme being implemented in England in the Yorkshire and Humber region, which was funded through the BIG Lottery and aimed to empower people across the region to lead better lives. The evaluation combined a systematic evidence review with semi-structured interviews across mental health and employment projects. Drawing on both evaluation elements, the paper examines the potential of workplace-based 'business champions' to facilitate organizational culture change within enterprises within a deprived regional socio-economic environment. First, the paper identifies key policy drivers for interventions around mental health and employment, summarizes evidence review findings and describes the range of activities within three projects. The role of the 'business champion' emerged as crucial to these interventions and therefore, secondly, the paper examines how champions' potential to make a difference depends on the work settings and their existing roles, skills and motivation. In particular, champions can proactively coordinate project strands, embed the project, encourage participation, raise awareness, encourage changes to work procedures and strengthen networks and partnerships. The paper explores how these processes can facilitate changes in organizational culture. Challenges of implementation are identified, including achieving leverage with senior management, handover of ownership to fellow employees, assessing impact and sustainability. Finally, implications for policy and practice are discussed, and conclusions drawn concerning the roles of champions within different workplace environments.