The heterogeneous nature of lignin poses significant obstacles to its practical use in material applications. Common fractionation methods employ harsh processing conditions that further exacerbate lignin's structural complexity. We propose a microwave (MW)-assisted approach for a mild organosolv extraction of structurally-intact lignin from spruce wood. The efficient energy transfer enabled by microwave irradiation facilitates the rapid extraction of lignin in 5, 10, and 20 minutes, ensuring a low level of process severity. Comparison of the 10 minutes MW-extracted lignin products with a cyclic-extracted (CE) organosolv lignin revealed that equivalent amounts of β-O-4 linkages were preserved in both processes. This is indicative of the promising potential of MW-extraction as a biomass pretreatment method for the rapid extraction of more native-like lignin. Finally, we demonstrate the utilization of both MW- and CE-extracted lignins as property-enhancing fillers in a biobased photocurable resin for digital light processing (DLP). The more native-like structures of the mildly-extracted lignins proved beneficial for functionalization with reactive methacrylate moieties, enabling the mechanical reinforcement of DLP 3D printed thermosets with improved toughness after the incorporation of only 1 wt% of the lignins. Compared to the resin without lignin, the tensile strength was improved by 15 and 41% and elongation at break by 79 and 75% in the presence of methacrylated MW- and CE-lignins, respectively. This highlights the potential of MW and CE strategies to effectively process and modify lignin, thereby enhancing its utilization in targeted material applications.