Zinc is one of the hazardous metals commonly found in municipal solid waste incineration (MSWI) ash, and this study reveals the stabilization mechanisms when sintering zinc-laden ash and ceramic precursors as a waste-to-resource strategy. Using ZnO to simulate the zinc-laden ash and sintering with kaolinite and mullite ceramic precursors, both zinc aluminate spinel (ZnAl 2 O 4 ) and willemite (Zn 2 SiO 4 ) phases were found in the products under the tested thermal conditions. The results also indicate that kaolinite and mullite precursors exhibit different incorporation behavior, and ZnAl 2 O 4 and Zn 2 SiO 4 were found to be competitive as the Zn-hosting phases in the system. A prolonged leaching test was used to evaluate the leachability of potential product phases in the system. The concentrations of zinc in ZnO and Zn 2 SiO 4 leachates were about two orders of magnitude higher than that in ZnAl 2 O 4 leachate, indicating the preference of forming ZnAl 2 O 4 for zinc stabilization. Furthermore, the aluminum-rich sludge generated from waterworks could be beneficially used as a material resource to stabilize zinc in this study. The X-ray diffraction (XRD) pattern collected from the 1150 °C and 3-h sintered sample shows the success of incorporating zinc into the ZnAl 2 O 4 spinel structure with waterworks sludge precursor. The formation of ZnAl 2 O 4 indicates a strong potential for employing aluminum- and silicon-based materials to thermally immobilize zinc and achieve the beneficial use of metal-laden MSWI ash.