Direct polymerization of allyl alcohol generally results in low molar mass oligomers or highly branched or cross-linked structures, and the properties and applications of linear, high molar mass poly­(allyl alcohol) (PAA) are relatively unexplored. Such macromolecular materials that cannot otherwise be obtained directly can be accessed by postpolymerization modification strategies. Herein we describe the synthesis and characterization of linear, high molar mass PAA by borohydride reduction of a new activated polyacrylamide. The facile polymerization and mild reduction conditions enable the preparation of PAA of targeted molar masses and low dispersity, as well as PAA block polymers via chemoselective reduction of the activated amide moiety.