Lang was married to Madalynne Field (1907–1974) from 1937 until his death. Field, a former Actress, had met and befriended Carole Lombard when they were employed as Sennett Bathing Beauties in the late 1920s. Field's film career ended with the demise of Sennett's studio. However, she maintained her friendship with Lombard, and acted as Lombard's secretary until her marriage. She met Lang when he directed Lombard in Love Before Breakfast (1936). Lang was buried in the Inglewood Park Cemetery, in Inglewood, California.
In 1925, Walter Lang directed his first silent film, The Red Kimono. In the mid-1930s, he was hired by 20th Century Fox where, as a Director, he "painted" a number of the spectacular colorful musicals for which Fox Studios became famous for producing during the 1940s. One of Lang's most recognized films is the lavish adaptation of Rodgers and Hammerstein's musical The King and I (1956) for which he was nominated for the Academy Award for Directing.