Intergenerational upward economic mobility–the opportunity for children from poorer households to pull themselves up the economic ladder in adulthood–is a hallmark of a just society. In the U.S., however, there are large regional differences in upward social mobility. The present research examined why it is easier to get ahead in some cities and harder in others. We identify the “walkability” of a city, how easy it is to get things done without a car, as a key factor in determining the upward social mobility of its residents. We first identify the relationship between walkability and upward mobility at the level of 741 community zones in the U.S. We find that this relationship is linked to both economic and psychological factors. Using data from the American Community Survey on over 3.66 million Americans, we show that residents of walkable cities are less reliant on car-ownership for employment and wages, significantly reducing one barrier to upward mobility. Additionally, in two studies (1745 Americans, 1466 Koreans), we find that people living in more walkable neighborhoods feel a greater sense of thriving (belonging to their communities, mastery, optimism, efficacy, and meaning in life), which is associated with increases belief about the possibility of upward mobility, and which in turn predicts actual real-world changes in individual social class.