Service users with severe psychiatric illnesses, such as schizophrenia, major depressive disorder and bipolar disorder, are more likely to suffer from ill health. There is evidence that lifestyle interventions, for example, exercise, dietary advice and smoking cessation programmes for service users with severe mental illness can be of health benefit. This review was carried out to identify the literature pertaining to physical health interventions for service users who have experienced a first-episode psychosis (FEP), to examine the nature of the interventions which were carried out and to assess these interventions in terms of feasibility and efficacy. A narrative review was conducted in August 2019 by searching 'Pubmed' and 'Embase' electronic databases. Studies investigating the effect a physical health intervention had on service users who had experienced a FEP were included in the review. Fifteen studies met inclusion criteria: 12 quantitative studies and 3 qualitative. Exercise, dietary advice, smoking cessation and motivational coaching were some of the physical health interventions utilised in the identified studies. Positive effects were seen in terms of physical health markers wherever they were investigated, particularly when the intervention was delivered early. The impact on psychiatric symptoms and longer-term impacts on health were less frequently assessed. Physical health interventions have a positive impact on service users who have experienced a FEP. More research is warranted in this area in Ireland. These studies should include controls, have longer follow-up periods and should assess the impact on psychiatric health.