Objectives: The current study aims to investigate outcomes and processes of an ultra-brief intervention, “marriage checkup (MC)”. Methods: A phenomenological qualitative methodology was applied for this study, in which seven married couples who have completed MC within seve7 months and three MC consultants were interviewed. Results: Five categories and 15 subthemes were identified. The five categories include motivation of participation, facilitative factors of change, experiences during intervention process, long-term experiences after completion of MC, and general reflection of MC. Conclusions: The study’s findings suggest that MC is a promising intervention for couple relationship health, in that it shows both short- and long-term positive effects on couples’ mental and relational health.