The integrated governance model was introduced in NHS organisations as part of the government's initiative to improve governance arrangements which were in silos. Alpha, as part of the larger NHS, embarked on the implementation of integrated governance immediately after it was publicised. This thesis explores the various aspects of organisational change involved in the adoption of a new governance framework. In particular, this thesis focuses on understanding the underlying reasons which trigger the need for change, explaining the process of change involved in the conceptualisation and installation of the integrated governance approach, and understanding organisational responses to change and the subsequent implications of the operationalisation of the new governance approach to the functioning of the board. The sensemaking approach is set out as an overarching theoretical framework to explain the empirical findings at Alpha. The sensemaking approach also borrows insights from the 'institutional context' and 'active agency' arguments to reinforce understanding of the factors that shape organisational change. Furthermore, it highlights the notion of ambiguity as an antecedent for sensemaking. This thesis argues that the adoption of integrated governance is a strategic response to institutional pressure to gain legitimacy from its higher governing bodies. The timing of the adoption, which was almost instantaneous despite the lack of guidelines from the government, suggests that the substantial driving force pushing the integrated governance agenda was internal. This argument led to the identification of the role of the institutional entrepreneur as the main impetus for organisational change. The ambiguous notion of integrated governance also triggers the sensemaking process enacted by the institutional entrepreneur. The seven properties of the sensemaking process (Weick, 1995) were appraised in explaining integrated governance change. Some properties were appraised more explicitly and appeared more relevant than others in explaining the change occurrence. Because of the context in which the board operated, the use of the integrated governance approach to inform the board process during public board meetings was downplayed. Arguably, understanding the operationalisation of integrated governance inadvertently sheds light onto the actual processes, challenges, complexities and dilemmas of the workings of a public sector board like Alpha's. In conclusion, studying the integrated governance change exemplifies the external and internal factors that jointly explain the nature, form and timing of change at Alpha. And appraising the outcome of change penetrates the 'black box' myth of board working, giving insights into what happens behind the closed doors of the boardroom. 8