Supported housing for people with mental and intellectual disabilities (IDs) is an important setting for health and may contribute positively and negatively to residents' health. The aim of this study was to explore health promotion practices and services in supported housing in Denmark using a mixed-methods design comprising qualitative group interviews with managers and employees (n = 12) and a nationwide survey among managers (n = 276) and employees from supported housing facilities (n = 315). This study showed that employees tried to integrate health promotion in the daily work with residents, but efforts primarily focused on individual behavior and motivation. Findings points to several challenges and barriers, including ambivalent attitudes towards smoking and beliefs that health promotion undermines self-determination and empowerment. To build supportive environments for people with mental and IDs, we need to focus on the attitudes, values and competences of managers and employees to tackle misconceptions about smoking, raise awareness about the wider determinants and promote structural changes.