Disclosed herein is an isosorbide-based polycarbonate polymer comprising: an isosorbide unit, an aliphatic unit derived from a C.sub.14-44 aliphatic diacid, C.sub.14-44 aliphatic diol, or combination of these; and optionally, an additional unit different from the isosorbide and aliphatic units, wherein the isosorbide unit, aliphatic unit, and additional unit are each carbonate, or a combination of carbonate and ester units. Also disclosed are a thermoplastic composition and an article comprising the isosorbide-based polycarbonate.