Growing evidence links psychological well-being (e.g., optimism) with superior cardiac health, but there remains a critical scientific gap as we do not know whether (or how) interventions to cultivate emotional well-being may reduce cardiac risk. Hispanics/Latinos in the U.S. have high cardiovascular disease risk and poorly controlled blood pressure (
BP
) compared to peers of European ancestry, and represent a population in need of new and innovative therapeutic approaches. This paper details the “¡
Alégrate!
” study, a cluster-randomized Phase II trial testing efficacy in improving BP of a culturally tailored positive psychological intervention designed to boost emotional well-being in Hispanics/Latinos with hypertension. A total of 126 Hispanics/Latinos aged ≥18 years, fluent in English or Spanish, and with elevated sitting BP (≥140/90 mmHg) will participate in one of two trial arms: (1) a positive psychological intervention, or (2) a wait-list control condition. The “¡
Alégrate!
” group-based intervention consists of 8 weekly 90–120-min sessions delivered in-person by a psychologist/social worker. Targeted skills include noting daily positive events, positive reappraisal of stressful events, effective expression of gratitude, performing acts of kindness, and regular practice of mindfulness and meditation, among others. The primary outcome is improvement in BP, both sitting values and 24-h ambulatory readings, as measured at baseline and 8- and 12-weeks post-baseline. Secondary outcomes include emotional well-being, engagement in healthful behaviors, and circulating levels of inflammatory markers. We hypothesize that BP control, psychological well-being, healthful behaviors, and chronic inflammation will be significantly better in the “¡
Alégrate!
” arm at follow up compared to the wait-list control group.