Helen Cam was born in 1885, the daughter of Rev William Herbert Cam, Head Master of Abingdon Grammar School, and Kate Scott. She was educated at home before going to Royal Holloway College, University of London, graduating with a BA in 1902. She received her MA, London, in 1909 after a Fellowship in History at Bryn Mawr College, Pennsylvania, 1908-1909. Professor Cam was also the recipient of several honorary degrees from British and American Universities. After a period as a schoolmistress (at Cheltenham Ladies’ College 1909-1912), Helen Cam returned to Royal Holloway College first as an Assistant Lecturer (1912-1917), then Staff Lecturer in History, 1919-1921. In 1921 she moved to Girton as Pfeiffer Research Fellow, (1921-1926), becoming Lecturer in History in 1926 and receiving a University appointment in 1930. She became a Fellow of the British Academy in 1945 and at the time of her departure from Girton held the position of Vice-Mistress.

In 1948 Harvard received endowment for the new Zemurray-Stone Chair, there was only one condition, the appointee had to be a woman, who would then be the first female to hold a Chair at Harvard. Helen Cam held the Chair from its creation to her (mandatory) retirement in 1954. She became a Fellow of the American Academy of Arts and Sciences (1950) and a Corresponding Fellow of the Mediaeval Academy of America.

Following retirement Helen Cam continued in academic life as Vice-President of the Selden Society, 1962 and Hon. Vice-President of The Royal Historical Society, 1963-68. She became an Honorary Fellow of Somerville College, Oxford, in 1964. Helen Cam received a CBE in 1957 for her services to education. She died in 1968.

Publications: "Local Government in France and England" (1912); "Studies in the Hundred Rolls" (1921); "The Hundred and the Hundred Rolls" (1930); "Liberties and Communities in Medieval England" (1944); "England before Elizabeth" (1950); "Crown, Community and Parliament in the Later Middle Ages", Gaillard T. Lapsley, (Ed) 1951; "Selected Historical Essays of F. W. Maitland", (Ed) 1957; "What of the Middle Ages is Alive in England today" (1961); "Law-Finders and Law-Makers in Medieval England" (1962); articles, lectures and county histories.