On 15 October 1930, Marshall married Katherine Boyce Tupper (8 October 1882 – 18 December 1978); They had no children, but she was the mother of three children with Baltimore lawyer Clifton Stevenson Brown. He had been murdered by a disgruntled client in 1928. The second Mrs. Marshall was a graduate of the American Academy of Dramatic Arts; she later studied at the Comédie-Française, and toured with Frank Benson's English Shakespearean Company. She authored a memoir, 1946's "Together: Annals of an Army Wife". One of Marshall's stepsons, Allen Tupper Brown, was an Army lieutenant who was killed in Italy on May 29, 1944. Another stepson was Major Clifton Stevenson Brown Jr. (1914–1952). Step-daughter Molly Brown Winn, who was the mother of actress Kitty Winn, was married to US Army Major James Julius Winn, who had been an aide to General Marshall.