On 5 May 1886 Molly Mitchell married Thomas Elder Barr Smith (1863-1941). The pair had six children. A company director and pastoralist, Thomas Elder Smith followed the philanthropic tradition of his father, Robert Barr Smith, and his uncle, Sir Thomas Elder. From the beginning of World War I Molly Barr Smith was an executive member of the South Australian branch of the British Red Cross Society. She was also chairman of the buying committee and co-ordinated the Red Cross Sock Club. On 4 October 1918, she was appointed C.B.E. (Civil) for services to the Red Cross in South Australia during the war. She died on the 16 June 1941, and is buried in Mitcham cemetery.

Sources used to compile this entry: Linn, R W, 'Smith, Tom Elder Barr (1863 - 1941)', in Australian Dictionary of Biography Online, Australian National University, 2006, http://www.adb.online.anu.edu.au/biogs/A110683b.htm; Joanne Cook, Research Librarian, State Library of South Australia.