AbstractGiven their ability to reduce activated alkenes thereby generating up to two stereogenic centers, ene reductases from the old yellow enzyme (OYE) family have received much attention as effective biocatalysts. Through genome mining, a “classical” OYE, KYE2, was identified from Kluyveromyces marxianus CBS4857 and fully characterized in vitro. This NADPH‐dependent enzyme displayed a broad substrate spectrum for the bioreduction of activated alkenes. The highly stereoselective synthesis (>95 % ee) of various (R)‐profen methyl esters, including the synthesis of (R)‐flurbiprofen methyl ester on a semi‐preparative scale further demonstrates the potential of KYE2 to be developed as a general biocatalyst for chemical synthesis.