We contribute to a revised politics of class in urban development by drawing on recent theoretical work on class tensions and inequalities as a barrier to more egalitarian and sustainable economic development. We provide evidence from an empirical study of the social dynamics of economic performance in the city of Kingston, Ontario, to argue that class politics is a key dimension of social dynamics in this unusually segmented and spatially segregated Canadian city. Our findings suggest that poor economic performance can be understood through a class lens in two ways. First, “creative class” economic development strategies and growth machine politics perpetuate economic stagnancy because they fail to confront underlying class inequalities. Second, the absence of collaborative and socially inclusive leadership—a contributor to poor economic performance—emerges when local institutional leaders fail to find common ground over social problems. We conclude with questions about how policymakers can alleviate class divides for better economic performance as well as contribute to the new debates in the literature on class and urban development.