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Melon fruit aroma depends on the balance between ester biosynthesis and hydrolysis, yet the carboxylesterase (CXE) family responsible for hydrolysis remains uncharacterized in this crop. Here, a genome-wide identification of the CXE gene family in melon revealed 22 CmCXE genes. Phylogenetic analysis revealed that Group III members cluster with functionally validated ester-hydrolyzing CXEs from peach, tomato, and strawberry, and their expression peaks during the climacteric and post-climacteric stages—the same window when melon aroma volatiles accumulate. We further functionally characterized CmCXE7, a cold-responsive member, through subcellular localization and heterologous overexpression in tomato. CmCXE7 localized predominantly to the plasma membrane with a weak nuclear signal. Non-targeted metabolomics revealed 776 differentially accumulated metabolites (DAMs) based on VIP > 1 and p < 0.05, with 11 of 14 high-magnitude ester-related changes being downregulated. These results identify Group III genes as candidate regulators of melon ester metabolism and identify CmCXE7 as a cold-responsive CXE candidate that may participate in ester metabolism. The potential relevance of CmCXE7 to fruit ripening and postharvest storage warrants further investigation, providing a candidate gene for future functional studies and molecular breeding of melon aroma quality.