Super El Niño events tend to recur on decadal timescales, but the underlying mechanism remains unclear. We show that decadal variations in ENSO amplitude are synchronized with the Tropical Pacific Decadal Dipole (TPDD), a zonal SST mode that modulates ENSO through the eastward and equatorward migration of the Intertropical Convergence Zone. This migration reorganizes background and ENSO-related convection, strengthening western Pacific air–sea coupling before El Niño onset and enhancing equatorial heat discharge during its decay. These processes amplify El Niño and the subsequent La Niña, respectively. These findings offer a potential predictor for super El Niño risks a decade in advance.