Abstract Background The rising prevalence of comorbidity has been described as an international health priority. There has been a dramatic increase in the levels of Type 2 Diabetes Mellitus (T2DM) among those with Acute Coronary Syndrome (ACS), with approximately 25-40% of patients admitted to hospital for ACS, also having diabetes. Comorbid ACS-T2DM provides a more complex set of symptoms for patients and clinicians to manage, and health policy makers to plan for. Those living with comorbid ACS-T2DM are at increased risk of death, another heart attack, re-hospitalisation, heart failure, reduced physical and psychological health, increased health service use and poorer quality of life. Due to shared disease determinants such as obesity, low physical activity levels and poorer dietary habits; individuals with ACS are more likely to have a comorbid T2DM. Care for patients with comorbidities is fragmented, siloed and poorly organised as it reflects a tradition of single disease management meaning comorbidity is rarely considered. Robust evidence is required to shape provision and guidance for those with comorbid ACS-T2DM and the clinicians involved in their care; with an emphasis on redesigning service provision and practice to address the needs of this growing population. Purpose To identify opportunities in existing clinical guidance to improve integrated care strategies and streamline management for those with comorbid ACS-T2DM. Methods Following Cochrane rapid review recommendations, a Population, Concept, and Context (PCC) framework guided eligibility. Guidelines for adults with ACS, T2DM, or both conditions in high-income countries were considered. Nineteen guidelines from the UK, Australia, Canada, Europe, Ireland, New Zealand, and the USA were compared, covering ACS (n = 10), T2DM (n = 6), and comorbid ACS-T2DM (n = 3). Lifestyle factors examined included diet/nutrition, physical activity, weight management, clinical and psychological aspects. Results The review identified consistent lifestyle recommendations for both ACS and T2DM, with overlaps in guidance for diet, physical activity, weight management, clinical, and psychological factors. The findings offer opportunity for integrated care strategies, potentially reducing duplicated lifestyle management efforts. The results lay the groundwork for more cohesive management of comorbid ACS-T2DM. Conclusions This research is relevant for healthcare providers, policymakers, and patients living with comorbid ACS-T2DM. Understanding the shared lifestyle factors provides valuable insights into the potential for integrated care. Recognising the overlap in existing clinical guidelines points to opportunity for a more streamlined and effective approach to managing comorbid ACS-T2DM. This knowledge can contribute to improved patient outcomes and seek to optimise healthcare resources.