Silylacetal was demonstrated to function as a promising cleavable moiety for preparing polymers degradable via desilylation under diverse, mild conditions. The silylacetal moieties were installed in the main chain of the polymers via the controlled cationic copolymerization of trimethylsilyl vinyl ether (TMSVE) and a cyclic acetal under appropriately designed conditions. Importantly, desilylation reactions of the silylacetal units occurred under weak acid, base, or fluoride ion conditions, which triggered the degradation of the polymer via the spontaneous cleavage of the unstable hemiacetal moieties generated by the desilylation. Moreover, silylacetal moieties were successfully incorporated at the desired positions in the main chain via the addition of a small portion of TMSVE during the controlled cationic copolymerization of a vinyl ether and cyclic acetal. The strategy devised in this study will allow the design of elaborate polymers that undergo degradation triggered by various stimuli.