As environmental change accelerates globally, understanding concurrent organismal, species, and community responses is increasingly vital. Here, we examine these coordinated responses by incorporating genotype-specific reaction norms into an eco-evolutionary predator-prey model, allowing us to track simultaneous phenotypic, ecological, and evolutionary responses to environmental change within ecological communities. We evaluate how different sources of phenotypic variation in thermal reaction norms influence eco-evolutionary outcomes across temperatures. Additive (E+G) and interactive (G×E) genetic and environmental effects on thermal reaction norms create distinct pathways through eco-evolutionary landscapes, yielding fundamentally different ecological and evolutionary dynamics across temperatures. Our findings underscore how complex eco-evolutionary responses to environmental change ultimately emerge from variation in reaction norms at the genotypic level, offering new mechanistic insight into adaptation, the maintenance of variation, and ecosystem stability that may be crucial for predicting and managing future eco-evolutionary impacts of rapid environmental change.