A brassy, blue-eyed platinum blonde of the 1930s in the Jean Harlow tradition. Joan was the daughter of Hollywood cinematographer Charles Rosher and appeared as a child in Mary Pickford movies (on which her father worked as cameraman) billed as Dorothy Rosher. She acted in some amateur dramatics as well but seems to have had little professional training. However, The Times in 1929 referred to her "extraordinary speaking and singing voice" at this crucial period when sound pictures began to replace silent cinema. When she was signed by Universal for La Féérie du jazz (1930), she adopted the stage name Joan Marsh. A fairly busy actress alternating leads and second leads throughout the decade and into the mid-40s, she is perhaps best remembered opposite Warner Oland in Charlie Chan à Broadway (1937) and as Dimples in En route vers Zanzibar (1941). Long under contract to MGM, she was also featured in two Greta Garbo films, L'inspiratrice (1931) and Anna Karenine (1935). In lighter fare her characters tended to have names like Beanie, Toots or Cuddles. It seems, Joan Marsh was also an accomplished dancer, especially adept at the two most popular dances of the era, the Charleston and the Black Bottom. On screen she performed a ballroom routine with Edward J. Nugent in Dancing Feet (1936). On radio, Joan replaced Beatrice Lillie as hostess of the musical variety show Flying Red Horse Tavern in 1936, as well providing the vocals for Lennie Hayton's Orchestra.Joan's first husband was the screenwriter Charles Belden, her second, a Captain John Merrill of Army Air Transport Command. Her hobbies included horse riding, tennis and golf. Joan retired from acting after her final picture for Poverty Row outfit Monogram in 1944 and in later years owned a Los Angeles stationary business, Paper Unlimited.