Enzymes originating from hostile environments offer exceptional stability under industrial conditions and are therefore highly in demand. Using single-cell genome data, we identified the alcohol dehydrogenase gene, adh/a1a, from the Atlantis II Deep Red Sea brine pool. ADH/A1a is highly active at elevated temperatures and high salt concentrations (optima at 70 °C and 4 M KCl), and withstands organic solvents. The polyextremophilic ADH/A1a exhibits a broad substrate scope including aliphatic and aromatic alcohols and is able to reduce cinnamyl-methyl-ketone and raspberry ketone in the reverse reaction, making it a possible candidate for the production of chiral compounds. Here, we report the affiliation of ADH/A1a to a rare enzyme family of microbial cinnamyl-alcohol dehydrogenases and explain unique structural features for halo- and thermoadaptation.