People with severe mental illness (PSMI) have a shorter life expectancy and are more likely to have cardiovascular disease than the general population. Patients, carers, psychiatric professionals and primary care providers can all play a role in increasing PSMI physical health. The present qualitative exploratory study aimed to explore the views of these four populations as part of the multi-phase COPsyCAT project, whose objective is to build and test a cardiovascular risk prevention programme for PSMI. Overall, 107 people participated in the study’s 16 focus groups, which were transcribed and analysed in a thematic analysis. With a view to building the health promotion programme, major themes identified in the corpus were translated into a list of needs as follows: communication, information, training and support. Results show that it is essential to improve communication between all the different stakeholders in mental health. The greatest challenge facing this programme will be to adapt it to the needs and expectations of PSMI while facilitating work between the various mental health stakeholders. Simple and inexpensive actions could be taken to improve the cardiovascular health of PSMI and will be experimented with during the programme’s feasibility study which will start in September 2022.