This study analyses the implementation and sustainability of evidence-based community mental health services in the form of publicly financed Individual Placement and Support programs. Critical implementation components and program fidelity were assessed after one year. After two years, program fidelity was assessed once again. After three years, the programs' sustainability was assessed and semi-structured interviews performed, in order to deepen the understanding of implementation. Interviews and documents provided the quantitative and qualitative data, which were analyzed by the use of the Supported Employment Fidelity Scale, the Sustainable Implementation Scale (which was developed in a connecting study), and qualitative content analysis. Despite promising fidelity results after one year, eight out of 14 programs were terminated within three years. Implementation of integrated evidence-based programs in community-based settings is a delicate undertaking. Implementing agencies can benefit from rigorous preparation before program start, especially concerning the circumstances at the organizational level, such as making plans for collaboration, financing and assessments of program fidelity.