In this paper, the authors study the direct and indirect effects of subjective well-being on physical health using mediation analysis. Subjective well-being is captured by two separate measures: one for overall life satisfaction and one for mental health. Using thirteen waves (2005-2017) of the data from the Household, Income and Labour Dynamics in Australia (HILDA) Survey, the authors consider physical activity, social interaction, smoking, drinking alcohol, outdoor tasks and volunteer or charity work as potential mediators. The authors find that the direct and indirect effects of past overall life satisfaction and past mental health are positively influenced present physical health. The indirect effects of this influence stand at 9.53% and 9.78% of the total effect of past overall life satisfaction and the total effect of past mental health, respectively, on physical health. Specifically, physical activity is a strong mediator in determining present physical health. As a result, for promoting better health, the design of health policies should consider both the direct and indirect effects of overall life satisfaction (or mental health) on physical health.