The reduced activation ferritic/martensitic steel Eurofer 97 is employed by many concept designs for the plasma-facing first wall of the EU DEMO fusion reactor. These designs feature precision joints between Eurofer 97 coolant piping for which novel laser-keyhole welding is one proposed technique. In this work, the microstructure of laser-keyhole Eurofer 97 welds is explored via CALPHAD-driven precipitate kinetics modelling supported by finite element thermal analysis. Microanalysis of a representative specimen via scanning electron and high-speed atomic force microscopy techniques is also conducted, complimented by electron backscatter diffraction, energy-dispersive X-ray spectroscopy, and nanoindentation hardness testing. Models of the weld microstructure agree well with the results of microanalysis although the precipitate diameters predicted are slightly underestimated. Several large void defects were discovered within the weld fusion zone, the cause of which is suspected to arise from evaporation during laser-welding of Ce-rich oxide inclusions in Eurofer 97.