Abstract The Maritime Continent (MC) has undergone rapid deforestation in recent decades, altering its land‐atmosphere energy balance. Using idealized Community Earth System Model simulations, we examined heat extremes under progressively increasing deforestation extents, from localized coastal clearing to complete forest removal. Surface and 2‐m air temperatures warmed nearly linearly with forest loss, whereas heat extremes responded nonlinearly, intensifying under moderate deforestation but weakening under severe deforestation. This weakening reflects spatially varying extreme‐heat responses across the MC, with extremes intensifying in some regions and weakening in others. The weakening is driven by reduced surface‐to‐atmosphere sensible heat, enhanced cold‐air advection, and cooler early morning temperature. Despite the weakening of dry‐heat extremes, wet‐bulb temperature increased following deforestation, indicating elevated human heat stress. These findings reveal that deforestation impacts on heat extremes are scale‐dependent and controlled by spatial heterogeneity, underscoring the need to incorporate realistic land‐surface feedbacks when assessing regional heat risk in tropical regions.