Complex sentence: His four Academy Awards for Best Director (1935,1940,1941,1952) are a record, and one of those films, "How Green Was My Valley", also won Best Picture.
Split into simpler sentences: His four Academy Awards for Best Director (in 1935,1940,1941, and 1952) remain a record. One of the films for which he won the award, "How Green Was My Valley", also won Best Picture.