Abstract: Improving carbon emission efficiency while sustaining high-quality economic development has become a critical challenge for regions pursuing ecological protection and green transformation in the context of China’s economic transition. As a key strategic region under China’s principle of “prioritizing ecological conservation and curbing excessive development”, the Yangtze River Economic Belt provides an important case for examining the interactive dynamics between carbon emission efficiency and economic development quality. Based on panel data from 108 prefecture-level cities between 2013 and 2022, this study constructs an integrated analytical framework combining the entropy weighting method, a super-efficiency slacks-based measure (SBM) model, a coupling coordination model, and a random-effects Tobit regression. The results indicate that both carbon emission efficiency and high-quality economic development in the Yangtze River Economic Belt exhibit upward trends over the study period, albeit with relatively modest growth rates. The degree of coupling and coordination between the two systems has also increased synchronously, yet the overall coordination level remains low. Spatially, the coupling coordination degree displays a clear “high in the east and low in the west” pattern, reflecting limited spillover effects from regional core cities. Further analysis reveals that industrial structure upgrading, technological innovation, external openness, and environmental regulation exert significant positive effects on coupling coordination, whereas energy-related pollution intensity has a pronounced inhibitory impact. These findings suggest that enhancing carbon efficiency governance requires improvements in performance evaluation mechanisms, stronger cross-regional coordination led by core cities, and the implementation of differentiated ecological regulatory policies to promote regionally coordinated green development.