This is an empirical quantitative study that uses urban demographic data to identify economic change in cities. Unlike previous demographic studies, a strong theoretical framework is provided for the analysis. The research is designed and interpreted through Jacobs’s theory of the city as economic process within the framework of Wallerstein’s modern world-system. This is the first time Jacobs’s theory has been subject to systematic inquiry over big time and big space. We create an inventory of 184 examples of Jacobs’s “explosive growth” from 1500 to 2005 within the modern world-system. These results are interpreted in terms of systemic hegemonic cycles with first Dutch, and then British, and finally U.S. cities dominating the inventory lists. It is found that Dutch, British and U.S. city growth spurts are front-loaded in their respective hegemonic cycles: this is strong evidence of hegemony being created and initially sustained through and by these dynamic cities. This study makes a direct contribution to developing world-systems analysis, and in a short conclusion future research on ways of contributing to Jacobs’s theory of the city are discussed.