Copolymerization of elemental sulfur (S8) with vinyl monomers to develop new polymer materials is significant. Here, for the first time, we report the anionic hybrid copolymerization of S8 with acrylate at 25 °C, yielding a copolymer with short polysulfide segments; i.e., each of them consists of only one to four sulfur atoms. The formation of a longer polysulfide segment would be ceaselessly disrupted by carbon anions through the chain-transfer reaction. The copolymer of S8 with diacrylate was cross-linked and exhibited excellent mechanical properties, with an ultimate tensile strength as high as 10.7 MPa and a breaking strain of 22%. Furthermore, the introduction of tertiary amide groups to the copolymer enabled it not only to be reprocessed via press molding at room temperature but also to exhibit self-healing properties without external intervention. This study provides a facile strategy to synthesize high-performance sulfur-based copolymers under mild conditions.