The implementation of digital government to improve the quality of public services requires transforming services from just "electronic" services to becoming more "smart" services. Therefore, the government needs a strategy and policy to prepare a foundation model to work properly to achieve this transformation goal. This study aims to develop and validate the foundation model for a smart government system suitable for Indonesia's government. The mixed-method based on the quantitative and qualitative approaches was used in this study to explore important dimensions and components of smart government, which further need to be validated based on the triangulation data sources. Data were collected from the literature review, in-depth interviews with experts, online surveys with Indonesia citizens, and focus group discussions. As a result, there are four dimensions, and eleven components founded important to design the models. Dimension one is infrastructure with two components, including ICT dan non-ICT. Dimension two is a structure with six components, including leadership, human resources, governance and management, structures bureaucracy, budget constraints, and planning and policy. Dimension three is a superstructure with two components, including Regulations and Laws dan Planning and Policy; dimension four is culture with two components, including organizational culture and individual culture. The structure dimension has been confirmed as the most important dimension for designing the foundation model, followed by infrastructure, superstructure, and cultural dimensions. This indicates that it is necessary to prepare the structure dimension and its components before adopting a smart government in Indonesia.