javascript:void(0) Ecological disturbance regimes are shifting and leaving behind novel legacies, like the remnant structures of dead foundation species, which have poorly known impacts on ecosystem resilience. We explored how dead coral skeletons produced by marine heatwaves–material legacies of increasingly common disturbances on coral reefs–influence spatial competition between corals and macroalgae. Following a heatwave, we removed dead skeletons from reef patches then used photogrammetry and AI-powered image analysis to quantify trajectories of coral and macroalgae. Skeleton removal yielded 60% more live coral and 50% less macroalgae relative to patches with skeletons left intact. Dead skeletons facilitated macroalgae development, and greater macroalgal abundance caused steeper declines in live coral. Lastly, removing skeletons stimulated four times more coral recruitment onto stable reef substrate. Our findings identify a promising avenue to manage for coral reef resilience and reveal how material legacies can alter physical environments to sway the outcomes of spatial competition.