Particular in service and b-to-b-sectors, employees’ brand commitment is a prerequisite for building a strong brand. While many areas of interest within the field of internal branding have been tested by empirical studies, knowledge of internally oriented brand ambassador programs (BAPs) is predominately anecdotal. The aim of this article is to identify BAPs’ success factors by first defining the corresponding term, followed by a BAP framework based on the literature, using 25 success factors in six categories. A longitudinal case study from the service industry tested the practical application of the framework, while the results of the case study were used to adapt the model. The findings show that a BAP is not an isolated instrument of internal brand management, but that its impact depends on important background factors such as brand orientation, brand management and C-level support. Overall, the updated BAP success factor model contains 31 factors. The research supports the planning and implementation of BAPs, as well as the monitoring of ongoing and the reflection of completed BAPs.