Electrospraying is an effective and facile technique for the production of micro- or nanoparticles with tailored sizes, shapes, morphologies, and microstructures. We synthesized functionalizable poly(styrene-random-glycidyl methacrylate) copolymers and used them to fabricate microparticles via the electrospray technique. The sizes and morphologies of the electrosprayed particles are controlled by altering the process parameters (feed rate and applied voltage), and the composition and thermodynamic properties of the polymer (i.e., compatibility of the polymer with the solvent). We further investigated modifying the surfaces of the electrosprayed particles with 3-mercaptopropionic acid by a simple and efficient thiol-epoxy "click" reaction as a proof-of-concept demonstration that desired functionality can be introduced onto the surfaces of these particles; the outcome was confirmed by various spectroscopic techniques. In addition, the epoxides within the particles easily undergo crosslinking reactions, enabling further effective particle stabilization. The results reveal that the structure and properties of the polymer can be used to fine-tune the structural parameters of the electrosprayed particles, such as their sizes and morphologies, which opens up the possibility of imparting a variety of desired chemical functionalities into the structures of stable organic materials via post-electrospray modification processes.