There is limited theory or knowledge regarding dietitians’ practice philosophies and how these philosophies are generated and incorporated into their professional practices. For the purposes of this study, a conceptual framework will explain and define the ‘philosophies’ as three different types of knowledge; episteme, techne, and phronesis. This study aimed to develop an explanatory theory of how dietitians in private practice source, utilise, and integrate practice philosophies. A grounded theory qualitative methodology was used to inform the sampling strategy, data collection, and analytical processes. Semi-structured interviews with dietitians in private practice were undertaken and data were collected and analysed concurrently. The results show that dietitians form collaborative relationships with their clients, in order to nurture change over time. They use intrinsic and intertwined forms of episteme, techne, and phronesis, which allow them to respond both practically and sensitively to their clients’ needs. The learning and integration of these forms of knowledge are situated in their own practice experience. Dietitians adapt through experience, feedback, and reflection. This study highlights that private practice offers a unique context in which dietitians deal with complex issues, by utilising and adapting their philosophies.