The initiative of Sponge City has been launched in China to manage stormwater in cities. This study aims to understand the motivation of professionals in advocating for sponge cities and their opinions on implementing sponge measures. This study surveyed 443 water and planning professionals who have been involved in sponge cities in South China, which is an area that is located in the subtropical climate zone with abundant rainfall and serious urban stormwater issues. A ‘crisis-action’ model that was established in this study revealed that professionals’ crisis awareness on urban flooding, water pollution and water scarcity would make them feel responsible for water protection, recycling and conservation, and the recognition of sponge cities as the advantageous solution would trigger their advocacy for the related policy. The professionals’ opinions on the feasibility of the sponge measures that have been proposed at the national level pointed to complex factors such as precipitation, urban density and cost-effectiveness in implementing Sponge City at the local level. This study also found some demographic differences in the responsibility and support for the Sponge City initiative. The results call for a more collaborative work platform for engaging various professionals in urban stormwater management.