Lukas trained for the stage at the Hungarian Actors Academy, and in 1916 he debuted on the Budapest stage. He soon became a local matinee idol, having appeared in many plays and films. He became well-known throughout Central Europe, and Max Reinhardt had him guest-star in Berlin and Vienna productions in the '20s. In 1927 Adolph Zukor brought him to the U.S., and from 1928 he made his career playing Continental Europeans in Hollywood films. At first he portrayed smooth, suave seducers; as age caught up with him he moved into villainous roles, and often played Nazis. His greatest acting triumph, however, came in an anti-Nazi role -- one of his few sympathetic parts at the time -- in Lillian Hellman's Watch on the Rhine on Broadway (1941); he reprised the role in the play's film version (1943), for which he won the Best Actor Oscar and New York Film Critics Award. He continued appearing in occasional films throughout the rest of his life, usually playing sympathetic old men.