The proliferation of digital mental health has resdesigned clinical and research practices. Digital mental health will continue to grow rapidly and have an impact on population health. However, disengagement in digital mental health interventions prior to experiencing intervention effects is common—despite advances in user-centered design. User-centered design includes end-users in digital mental health intervention development and is intended to increase the usefulness and satisfaction with technology, and hence, impact engagement with technology. Despite efforts to include end users in the usability testing process, disengagement is still highly common. User-centered design methodology alone is not capturing the full potential of end users, and in some cases, resulting in unforseen consequences of perpetuating health and healthcare disparities for vulnerable populations. For example, people with serious mental illness have a reduced life expectancy of 11-30 years compared to the general population. As such, their biologic, health care system factors, and social influences on health are different than that of the general population and beset with poverty, stigma, discrimination, and poor access and underutilization of health care. As such, including people with serious mental illness (end-users) as equal partners in digital mental health development and implementation can offer valuable perspectives and insights into addressing the needs of populations within the context of their social and physical environments.