She was born in Islington, London, the eldest daughter of a wholesale dairy manager.
[1] A full professor at the age of 34, Lillian Penson served as a member of the University of London senate for 20 years.
Her accession to this office was put into perspective by a writer who said: "It was not the fact that she was the first woman to become chancellor of a University in the Commonwealth which attracted attention, but rather her vigorous, purposeful, and clear-headed approach to the many problems which the University of London faced."
Her primary subject of academic expertise, were the life and diplomatic statecraft of the last Victorian Prime Minister, Lord Salisbury, as well as the foreign policies of European Powers preceding the First World War.
[1] In 2017, she featured in a conference, London's Women Historians, held at the Institute of Historical Research.