Young adults (18-39 year-olds) with hypertension have a higher lifetime risk for cardiovascular disease. However, less than 50% of young adults achieve hypertension control in the United States. Hypertension self-management programs are recommended to improve control, but have been targeted to middle-aged and older populations. Young adults need hypertension self-management programs (i.e., home blood pressure monitoring and lifestyle modifications) tailored to their unique needs to lower blood pressure and reduce the risks and medication burden they may face over a lifetime. To address the unmet need in hypertensive care for young adults, we developed MyHEART (My Hypertension Education And Reaching Target), a multi-component, theoretically-based intervention designed to achieve self-management among young adults with uncontrolled hypertension. MyHEART is a patient-centered program, based upon the Self-Determination Theory, that uses evidence-based health behavior approaches to lower blood pressure. Therefore, the objective of this study is to evaluate MyHEART's impact on changes in systolic and diastolic blood pressure compared to usual care after 6 and 12 months in 310 geographically and racially/ethnically diverse young adults with uncontrolled hypertension. Secondary outcomes include MyHEART's impact on behavioral outcomes at 6 and 12 months, compared to usual clinical care (increased physical activity, decreased sodium intake) and to examine whether MyHEART's effects on self-management behavior are mediated through variables of perceived competence, autonomy, motivation, and activation (mediation outcomes). MyHEART is one of the first multicenter, randomized controlled hypertension trials tailored to young adults with primary care. The design and methodology will maximize the generalizability of this study. TRIAL REGISTRATION: ClinicalTrials.gov Identifier: NCT03158051.