Typhoons, fueled by warm sea surface waters, heighten concern as they increasingly interact with frequent Marine Heatwaves (MHWs) in a changing climate. Typhoon Hinnamnor (2022) weakenned and re-intensified as it approached the Korean Strait, interacting with underlying MHW in the northern East China Sea (nECS). Here, we found a substantial increase in latent heat loss from the nECS during the MHW period, contributing to the typhoon re-intensification from in-situ observations supplemented by reanalysis products. Strong sea surface wind forcing associated with the typhoon enhanced vertical mixing and upwelling, resulting in a pronounced (0.90°C) sea surface cooling after the typhoon passage, facilitating MHW dissipation with reduced thermal stratification. Such changes in background stratification, furthermore, significantly weakened semidiurnal internal tides due to unfavorable condition for generation from a nearby source. These findings underscore the importance of continuous time-series observations for monitoring interaction processes among the extremes in a changing climate.