Tunnicliff practiced law in Massachusetts and Illinois, and taught at Cornell University. She was also director of a children's home in Ithaca. She is best known as main author of the five-volume Judicial Cases Concerning American Slavery and the Negro (1926–1937), written with support from the Carnegie Foundation. Her work remains a useful source on the legal history of slavery in the United States, and is still referenced in controversies on the subject, almost a century after its publication.
