A continuous method of steam gasification through hybridization of a solar reactor with an autothermal gasification process is proposed and tested. The ability to autothermally gasify a carbonaceous feedstock within a solar reactor enables round-the-clock production of syngas regardless of solar transients. Associated changes in syngas composition and production rate are explored through equilibrium compositions. Partial feedstock combustion results in an associated drop in syngas quality, although H2 and CO are still the primary chemical constituents. Monte Carlo ray-trace modeling was performed to examine the effect of different prototype reactor configurations on heat flux distributions. A prototype reactor was fabricated and tested in a high-flux solar simulator, and time-averaged responses to different inlet conditions were analyzed. Product gas compositions resembled those predicted using equilibrium calculations. Cold gas ratio values greater than unity indicated energetic upgrade of the feedstock and the storage of simulated solar energy within the chemical bonds of the product gases.