Group transfer radical polymerization (GTRP) proves to be a robust strategy for radical polymerization, which has been applied to the construction of carbon-chain polyolefins. We conceive to explore a new polymerization pattern harnessing sulfonyl radical-mediated GTRP for the production of aliphatic polysulfones, where the strategically designed sulfone-substituted α-olefins are employed as monomers (Fig. ). Mechanistically, the alkyl radical (a) derived from the addition of an initiating radical to α-olefin triggers the intramolecular Smiles rearrangement via 1,4 or 1,5-cyclic transition state, generating a sulfonyl radical species (c) with the SO2 unit retained in the structure. This electrophilic radical species rapidly adds to another olefinic monomer, enabling a kinetically favored propagation process. Herein, we report the proof-of-concept study, where a series of aliphatic polysulfones is produced with high molecular weights (up to 199 kg/mol) and remarkable low distributions compared to existing methods. The GTRP proceeds via a SO2-free process, giving rise to various ABC sequence-regulated polymers, analogous to the ternary copolymers from conjugate olefin, ethylene (or cyclopropane), and SO2, otherwise highly difficult to prepare by other methods. Notably, this is the first example of applying Smiles rearrangement in radical polymerization.