Her family was deeply involved in show business. Her father, Lew Fields, was a Jewish immigrant from Poland who partnered with Joe Weber to become one of the most popular comedy duos near the end of the nineteenth century. They were known as the Weber and Fields vaudeville act. When the duo separated in 1904, Lew Fields went on to further his career in another direction, by becoming one of the most influential theater producers of his time. From 1904 until 1916, he produced about 40 Broadway shows, and was even nicknamed “The King of Musical Comedy” because of his achievements. Her mother was Rose Harris. She had two older brothers, Joseph and Herbert, who also became successful on Broadway: Joseph as a writer and producer and Herbert as a writer who later became Dorothy's collaborator.