Purpose – The purpose of this paper is to explore how a sustainability manager, embodying the role of change agent, legitimizes the implementation of Integrated Reporting. By focusing on an Italian public utility, operating in the electricity sector and listed on the Italian stock exchange, which has recently implemented the Integrated Report, this paper unveils how a voluntary change (i.e. the adoption of the Integrated Report) can be achieved thorough the legitimizing work carried out by a sustainability manager driven by strong intrinsic engagement, availability of resources and intense networking.

Design/Methodology/Approach – The case study methodology was adopted to reach the purpose of this research. A longitudinal and explanatory case study was realized by analyzing data collected from different sources. Relevant information was extrapolated from various corporate documents, visit to the case organization and thirteen in depth interviews conducted with sustainability managers, finance managers, communication managers and human resources managers. After triangulating data, findings were analyzed through the lens of institutional entrepreneurship which is the branch of neo-institutional theory explaining how actors can drive substantial changes.

Findings – This study uncovered how the adoption of Integrated Reporting – which requires a substantial change in organizational structure, processes and thinking – can be achieved over time through the perseverance of a sustainability manager who strives to legitimize his individual position and strengthen the value of the whole Corporate Social Responsibility (CSR) area within the organization. Such perseverance, necessary to initiate and achieve the desired change, can be successful when the change agent uses available resources and networking skills, to gain support from various groups with different power balances, and to enable people of different organizational areas to collaborate to the end of preparing the Integrated Report.

Research limitations/implications – This research highlights that when people belonging to different organizational areas perceive the added value of implementing a substantial change, they engage in alternative practices and show availability to collaborate. Still, the reluctance to share strategic information in the light of its disclosure in the Integrated Report is perceived, meaning that bridging the gaps between finance and sustainability managers requires more efforts. The true transformation of organizational values and beliefs, in line with the ideas of Integrated Reporting, requires the full acceptance and practice of integrated thinking on each level of the organization.

Practical implications – This paper shows that the voluntary implementation of Integrated Reporting is possible when the reporting tool is not only perceived as a disclosure document, but also as a vehicle that increases the awareness and sharing of corporate integrated value. People in different areas interact in a different way facilitating the horizontal integration of operational activities.

Originality/Value – as an emerging phenomenon, literature has focused on many aspects of Integrated Reporting. This paper adds value to recent debates by focusing on how individual actors legitimize their projects within their organization by highlighting tensions and how they can be overcome to achieve the desired change.