Diacetone is widely used to form chelates with various metals. Polymer materials containing acetylacetone have great potential for catalytic reactions, the separation of heavy metals, and luminescent materials. In this report, we chose 2-(acetoacetoxy)ethyl methacrylate (AAEM) as a functional monomer. We synthesised monodisperse polymethylmethacrylate (PMMA) with diacetone on the surface via one-step RAFT-assisted dispersion photopolymerisation using P(AAEM-co-mPEGA) as a stabiliser. This type of functional microsphere can be used for catalysis after the adsorption of TiO2. Using 2-(acetoxy)ethyl methacrylate (AAEM), methyl methacrylate (MMA), and dipropylene glycol diacrylate (DPGDA) as crosslinking agents and the poly(acrylamide N,N-dimethyl) macromolecular RAFT reagent (P(DMA)-TTC) as a stabiliser, we obtained other functional microspheres using diacetone. These microspheres can be further utilised as magnetic microspheres by swelling in DMF and adsorbing iron and ferrous ions. We also evaluated the magnetic content and thermal stability of microspheres with different AAEM and MMA monomer ratios. Polymer microspheres have great potential in various applications owing to their excellent monodispersibility, superparamagnetism, and easy separation. Our study provides a new, simple, and effective method for preparing surface- and internal-functionalized microspheres.