Heart failure self-management can be complex and challenging. We are collaborating with healthcare professionals, patients and families to co-design a consumer mHealth application in support of heart failure self-management. Four patient-modelled personas, developed through ethnographic interviews, were used in co-design workshop activities to represent the patient experience and associated health challenges. We explain how persona use benefited patients, the design team and the project lead in terms of efficiency, effectiveness and anonymity, in our commitment to developing a mHealth application which meets the needs of our patients and is clinically relevant.