The daughter of Dr. Frank Morgan and Sheila Saddler, she was born Janet Morgan in Montreal while her father was working on a top-secret British atomic research project, the Montreal Laboratory. She returned to England with her family before the end of World War II. She earned a MA and PhD. She was named a Commander in the Order of the British Empire in 2008. She is a fellow of the Royal Society of Edinburgh and an International member of the American Philosophical Society.
She has been chair of the Scottish Cultural Resources Access Network, the Nuclear Liabilities Fund and the Nuclear Trust. She has served as a director of the Scottish Oriental Smaller Companies Trust and Murray International Trust.
Morgan wrote a biography of Agatha Christie that was authorized by the writer's family. She also wrote biographies of Edwina Mountbatten and George Bruce, her father-in-law and the previous Lord Balfour of Burleigh. She was editor for The Backbench Diaries of Richard Crossman.
- "Lady is 'a real person' at last". Montreal Gazette. November 27, 1999.
- "Dr. Janet Morgan". The Peerage.
- "APS Member History". search.amphilsoc.org. Retrieved 2021-03-22.
- "Janet P. Morgan". Bloomberg.
- "The Balloonist and the Housewife - A daring tale of espionage during the First World War". Clackmannanshire Council.