In June 1919, Margaret was first employed as a typist in the Law School at the University of Sydney. and during World War II was secretary for the Law School Comforts Fund, sending monthly parcels of books to law students serving in the forces. She also compiled the
Legal Digest, a quarterly newsletter intertwining gossip about members of the profession with information on legislative changes. Keen to assist servicemen studying law by correspondence, she forwarded teaching materials and textbooks, and arranged tutoring and examinations. Hay's career spanned the development of the Law School into a large postwar faculty, covering the changeover from
John Peden's deanship to that of
Kenneth Shatwell. During this period, she became an associate-member of the
National Council of Women of New South Wales and joined the National (late
United Australia) Party. She had several articles published in
The Sydney Morning Herald and left behind several unpublished works including a biography of
Sir Thomas Bavin and a history of T. J. Thompson's family and stockbroking firm, revealing both her dedication to the legal profession and her political conservatism. Hay retired in December 1953 with a holiday in England and spent the following 60's working part-time in the law library. ==Death==