She had a Quaker education at Brighthelmston, at Birkdale in Southport, Lancashire, about 1896–7, and The Mount, in York, from about 1897 to 1900, before studying medicine at Birmingham University and the Royal Free Hospital, London where she graduated M.B.
[4] Together with her life-long friend Edith Pye, a nurse and midwife, Clark founded and ran a maternity hospital at Chalons-sur-Marne from 1914 to 1918.
[citation needed] She was also an early supporter of the British Society for the Study of Sex Psychology, an organisation concerned with societal acceptance of homosexuality.
Clark travelled to Vienna to use her expertise and connections in generating documentation, placements and qualifications for Jewish people to aid their escape.
"Only those most closely concerned can know what the work owed at this stage of rapid expansion to the steady faith and practical experience on Hilda Clark.