Leadership in public health is necessary, relevant, and important as it enables the engagement, management, and transformation of complex public health challenges at a national level, as well as collaborating with internal stakeholders to address global public health threats. The research literature recommends exploring the journey of public health leaders and the factors influencing leadership development, especially in developing countries. Thus, we aimed to develop a grounded theory on individual leadership development in the Nepalese context. For this, we adopted constructivist grounded theory, and conducted 46 intensive interviews with 22 public health officials working under the Ministry of Health, Nepal. Data were analysed by adopting the principles of Charmaz's constructivist grounded theory. The theory developed from this study illustrates four phases of leadership development within an individual-initiation, identification, development, and expansion. The 'initial phase' is about an individual's wishes to be a leader without a formal role or acknowledgement, where family environment, social environment and individual characteristics play a role in influencing the actualisation of leadership behaviours. The 'identification phase' involves being identified as a public health official after having formal position in health-related organisations. The 'development' phase is about developing core leadership capabilities mostly through exposure and experiences. The 'expansion' phase describes expanding leadership capabilities and recognition mostly by continuous self-directed learning. The grounded theory provides insights into the meaning and actions of participants' professional experiences and highlighted the role of individual characteristics, family and socio-cultural environment, and workplace settings in the development of leadership capabilities. It has implications for academia to fulfill the absence of leadership theory in public health and is significant to fulfill the need of leadership models grounded in the local context of Asian countries.