Daughter of Henry Walter Flewett, born in 1892, and Winifred Johnson Flewett, born in 1896, who passed away in 1967. She was educated at the prestigious Sacred Heart Convent School, a Roman Catholic institution in London, and later honed her craft at the renowned Royal Academy of Dramatic Arts from 1945 to 1947.
During World War II, she found herself evacuated with her school to Oxford, where she took on the role of a volunteer housekeeper and hen-keeper in the household of the celebrated author C.S. Lewis. This experience led her to defer her acceptance of a place at RADA on several occasions.
In 1980, she co-founded Jill Freud and Company, a non-profit repertory company dedicated to the art of theatre. Her tireless efforts in the field of drama were recognized in 2001, when she received an Honorary Doctorate in Civil Law from the University of East Anglia "for services to the theatre".
Jill Freud's personal life was marked by a significant union with writer Clement Freud, grandson of the esteemed Sigmund Freud, whom she married on September 4, 1950. Clement went on to become a Member of Parliament for the Isle of Ely from 1973 to 1987, was knighted in 1987, and later served as the rector of St. Andrew's University in 2003. Following his knighthood, Jill Freud became "Lady Freud".
