We report a study starting with suberin fatty acid (SFA) extraction (biorefinery) and characterization, followed by cellulose nanocrystal (CNC) modification to prepare suberin brushes on cellulose, and finally, the assessment of obtained modified cellulose nanocrystal filler (CNC) suitability as reinforcement in bio-based acrylate resins. The research establishes a deep focus on chemical structure characterization, with methods like FTIR and NMR as the basis for proving the proposed interactions and modification reactions. The changes in SFA acid group content and formed surfaces on the functionalized CNC were thoroughly analyzed with titration, TGA, FTIR, and AFM. Lastly, the application of modified nanoparticles is tested in bio-based resins based on acrylated vegetable oils. The DLP 3D-printing approach is validated to the exceptional detail resolution, compatibility, and use of an energy-efficient photo-curing process. Using only 0.1 wt% of functionalized CNC, a significant enhancement in mechanical performance was achieved. The colorimetric assessment, FTIR, AFM, tensile and flexural tests, and dynamical mechanical analysis were used to provide a complex analysis of the interface, dispersion, and nanoparticle interaction with the polymeric matrix.