Optically active and highly coherent emitters in solids are a vital component for building future quantum networks that will enable modular quantum computing, secure quantum information sharing, and distributed quantum sensing. Rare-earth atoms in solids have several important properties for building the practical quantum photonic devices that will serve as the backbone of any useful quantum network. My research program uses hardware-aware design principles to develop new rare-earth materials and platforms as well as new quantum protocols for practical quantum networking devices. I will give an overview of quantum networking with solid-state emitters and present recent research results including the characterization of a new stoichiometric rare-earth crystal with narrow linewidth and record high emitter density, as well as photonic integration of rare-earth doped materials in chip-scale platforms for quantum light storage and processing.