When would perceptions of economic mobility enhance individuals’ subjective well-being? The current research examined the moderating effect of perceived social support on the relationship between perceived economic mobility and subjective well-being. We found that perceived economic mobility increased subjective well-being more among people with high perceived social support than among those with low social support. This interaction effect was robust across a secondary data study with South Korean participants (Study 1) and two online studies with U.K. samples (Studies 2 and 3) even when controlled for the effects of subjective SES (in Study 1), household income (in Studies 2 and 3), age, and gender. Willingness to spend future earnings on others was revealed as an underlying mechanism. Specifically, among people with high (vs. low) perceived social support, perceived economic mobility enhanced subjective well-being via heightened willingness to spend future earnings on others, ruling out an alternative reason for subjective well-being such as perceived importance of money.