In this review, we present our recent research progress at the Naval Research Laboratory in the development of highly transparent and rugged ceramic window materials such as MgAl2O4 spinel and β-SiC; high-power solid-state laser gain materials based on sesquioxide such as Yb(3+):Y2O3, Yb(3+):Lu2O3, and Ho(3+):Lu2O3; and composite ceramics in the application for high-energy lasers. Various powder synthesis/purification methods and powder post-process techniques necessary to create high-purity powders are described. Ceramic fabrication processes and chemical, morphological, and optical properties of the ceramics developed at the Naval Research Laboratory (NRL) are highlighted. We also report high-efficiency lasing from a hot-pressed rare-earth sesquioxide single layer and composite ceramics made from coprecipitated powder.