Abstract Research purpose. The study explores the impact of transformational leadership on innovative employee behaviour, with tacit knowledge sharing as a mediator. This contributes to existing literature on the dynamic interplay between transformational leadership, employee innovation, and tacit knowledge sharing within organisational contexts. Design / Methodology / Approach. The study used a cross-sectional research design to examine relationships between the variables. 450 questionnaires were distributed among white-collar employees in Greater Jakarta, and a high response rate of 91.2% was achieved. Using the widely accepted Partial Least Squares Structural Equation Modelling technique, the study further analysed the hypothesised relationship among transformational leadership, tacit knowledge sharing, and innovative work behaviour. Findings. As evident from the study, transformational leadership would play a major role in influencing the level of sharing of tacit knowledge among employees and, therefore, would result in a supportive, innovative environment. It also has a direct effect on the employees to behave in an innovative way by the inculcation of new ideas or changes. Tacit knowledge sharing is positively related to innovative behaviour. Transformational leadership also indirectly affects innovative behaviour via tacit knowledge sharing. The model explaining these linkages was also further evidenced to be effective through the conduction of structural equation modelling. Overall, the results underline transformational leadership as a critical success factor for a knowledge-sharing culture and innovation development within the organisation, either directly or indirectly. Originality / Value / Practical implications. The research topic area also encompasses the role of tacit knowledge sharing in mediating the relationship of transformational leadership with innovative work behaviour and, hence, reveals the connection between leadership and innovation through knowledge exchange. It places transformational leadership in a discourse of knowledge management and outcomes of innovation, which points to the general importance of intangible assets and specifically to knowledge sharing. The empirical findings supported the idea that transformational leaders provide a climate where sharing tacit knowledge is an important aspect of organisational innovation. This review, therefore, focuses on the knowledge management, innovation, and leadership literature, with the aim of providing a multidisciplinary overview that would be helpful for readers in management, organisational psychology, and business innovation. This is the approach of leadership development by organisational leadership. HR professionals need to focus on strategies supporting the inculcation of a culture of sharing tacit knowledge around innovation. It ought to support measurement approaches for evaluating effectiveness in leader-led efforts to promote innovation and knowledge exchange.