Abstract The Clumping Index (CI) critically regulates canopy radiation, yet its role in reshaping global heat fluxes under land‐atmosphere (L‐A) interactions remains poorly quantified. We integrated satellite‐derived CI into the Community Earth System Model (CESM) to assess its impacts through L‐A coupled simulations. Results show that CI systematically shifts energy partitioning by increasing ground sensible heat and evaporation while reducing vegetation counterparts, with spatial patterns modulated by L‐A coupling. Rather than acting as a uniform amplifier, L‐A coupling modifies the regional expression of CI‐induced flux changes through atmospheric feedback pathways. Comparisons with FLUXCOM and flux‐tower observations provide complementary large‐scale and site‐level context, and suggest that including CI together with L‐A coupling generally improves simulated sensible and latent heat fluxes across most plant functional types, with needleleaf vegetation as an exception. Our study provides new insights into how vegetation structure regulates global energy balance within the L‐A coupling framework.