Using data from six waves of the Study of Marital Instability over the Life Course (N = 1,998), we conducted a latent class analysis to test for distinct marital happiness trajectories. We found three distinct marital happiness trajectories: low, middle, and high happiness. Initial levels of life happiness were strongly associated with membership in the marital happiness trajectories and with various demographic and attitude-related control variables. Using fixed effects regression with time-varying covariates, we also found that marital happiness trajectory membership was associated with subsequent changes in both life happiness and depressive symptoms. All respondents experienced a decrease in life happiness between Wave 1 and the end of their observed time in their marriage, but respondents in the high marital happiness trajectory experienced the smallest decline. Respondents in both the high and middle marital happiness trajectories also experienced a decline in depressive symptoms across time. Intervention and policy implications are discussed.