The strategic exploration of urban sports tourism resources and the pursuit of novel trajectories for urban growth are pivotal for resource integration and competitive enhancement within cities. This investigation concentrates on Chinese city marathons and compiles daily search index data from Baidu for 38 city marathons across the nation, spanning from January 1st, 2012 to May 3rd, 2022. Employing time series clustering to evaluate the data, and in conjunction with indices related to urban tourism resources and city development, we delve into the characteristics of how Chinese city marathons propel urban growth. The findings illustrate that the search index data for the 38 city marathons can be clustered into three categories, with Xi’an, Fuzhou, and Dalian emerging as the epicenters of clustering. The representative search index data for these three clusters reveal diverse characteristics of change. The search index shifts for three landmark races align generally with the changes observed in their respective cluster center races, however, variations exist among the search index changes for these iconic marathons. The degree of search index and its trending direction in city marathons emanate from the synergistic influence of the city’s political, economic, and tourism attributes, in addition to the event’s prominence. City marathons also catalyze urban development through economic stimulation, image enhancement, and infrastructure improvement. Future exploration of novel trajectories for urban development could be facilitated through harnessing the economic and tourism attributes of these events, and by orchestrating a unified series of marathons.