In today's rapidly evolving business landscape, characterized by technological advancements, organisations are placing significant emphasis on digital transformation (DT) to survive. Concurrently, considerations of sustainability impacts have become crucial factors that organisations must take into account. The combination of the two is known as a sustainable digital transformation (SDT). There is currently a lack of research on how the organisational change of an SDT can occur. In particular, there is a lack of management tools that managers can use to actualise SDT. The actualisation of a SDT is what this study looks to explore by contextualising an organisational change model, known as Kotter’s 8-step model, to an SDT. The aim of the thesis was to provide guidance to practitioners on how to implement an SDT, and to add new knowledge to the theoretical understanding of how Kotter's 8-step model can be contextualised to an SDT. The thesis utilised semi-structured interviews and thematic analysis, identifying 18 activities that can be executed during an SDT initiative across the 8 steps of Kotter's model. These 18 activities extend existing knowledge by emphasising the importance of highlighting the need for change in relation to sustainability, financial, and diverse stakeholder perspectives. The thesis also contributes new insights by emphasising the significance of engaging external actors such as regulatory bodies, like-minded businesses, and industry associations. During the vision for change phase, we found the necessity of strategically drawing out a long-term strategy that corresponds with sustainability goals, rather than solely focusing on immediate wins for leadership. Furthermore, our study highlights the value of providing training to overcome resistance to digital change and enhance digital literacy, acknowledging that digital transformation is a time-consuming process. Lastly, we found that sustaining an SDT requires retaining and promoting change leaders and selectively hiring individuals who align with the change, as reverting to previous practices can hinder progress. For future study it is recommended that further interviews be conducted with relevant professionals, and that a case study or observational study be done with an organisation that conducts an SDT using Kotter's model.