A comprehensive evaluation of carbon emission efficiency (CEE) and identification of paths to improve it are crucial for achieving sustainable development goals, yet existing studies have limitations. This study employs the super-efficiency SBM model to measure the CEE of 284 Chinese cities from 2003 to 2022 and uses qualitative comparative analysis to examine the driving paths for improving CEE. The study finds that: (1) from the perspective of CEE measurement results, China’s CEE shows a U-shaped trend from 2003 to 2022; (2) regarding the influencing factors of CEE, high CEE is not driven by a single factor but by the combined effect of multiple factors, and the study identifies three functional paths: the energy efficiency and industrial structure-driven path, the energy efficiency and population density-driven path, and the energy efficiency, industrial structure, and population density-driven path. This study provides new insights for the government to implement targeted policies to promote the improvement of CEE.