Despite improvements in mortality rates over the past several decades, cardiovascular (CV) disease remains the leading cause of death for African-Americans (AAs). Innovative approaches through mobile health (mHealth) interventions have the potential to support lifestyle change for CV disease prevention among AAs. We aimed to translate a behavioral theory-informed, evidence-based, face-to-face health education program into an mHealth lifestyle intervention for AAs. We describe the design and development of a culturally relevant, CV health and wellness digital application (app) and pilot testing using a community-based participatory research (CBPR) approach with AA churches.This mixed methods study used a 4-phase iterative development process for intervention design with the AA community. Phase 1 included focus groups with AA community members and church partners (n = 23) to gain insight regarding potential app end user preferences. In Phase 2, the interdisciplinary research team synthesized Phase 1 input for preliminary app design and content development. Phase 3 consisted of a sequential 3-meeting series with church partners (n = 13) for iterative app prototyping (assessment, cultural tailoring, final review). Phase 4, a single group pilot study among AA church congregants (n = 50), assessed app acceptability, usability, and satisfaction.Phase 1 focus groups indicated general and health-related apps preferences: multifunctional, high-quality graphics/visuals, evidence-based, yet simple health information and social networking capability. Phase 2 integrated these preferences into the preliminary app prototype. Phase 3 feedback was used to refine the app prototype for pilot testing. Phase 4 pilot testing indicated high app acceptability, usability, and satisfaction.This study illustrates integration of formative and CBPR approaches to design a culturally relevant, mHealth lifestyle intervention to address CV health disparities among AAs. Given the positive app perceptions, our study supports the use of an iterative development process by others interested in implementing an mHealth lifestyle intervention for racial/ethnic minority communities.Clinicaltrials.gov NCT03084822.