Jean Sanville was born on December 6, 1918, in Tionesta, Pennsylvania, to Forest Johnson, a physician, and Ruth Dimon, a school principal. Sanville became interested in psychoanalysis at a young age, picking up Karl Menninger's book The Human Mind. "Being a bit worried about my own [mind] at the time, I read it cover to cover and was really turned on by psychoanalysis as he portrayed it... I was transfixed by some paragraphs that described a budding new profession, psychiatric social work." Wishing to study psychoanalysis, she earned her Bachelor of Arts degree from the University of Colorado in Boulder in 1940, her Master of Social Sciences from Smith College in 1942, and her Ph.D. from the International College in Los Angeles in 1943. She married Richard Sanville, and they have two children—Joan Palmer and Peter Livermore.

After getting her Master's degree, she worked as a caseworker for family service agencies in New York, Pittsburgh, and Los Angeles. She was awarded her Ph.D. in 1946. Sanville went on to work as a psychiatric social worker at Veterans Administration in Los Angeles, then as a psychotherapist for Hacker Psychiatric in Beverly Hills, and then finally opened her own practice in 1958 in Los Angeles. All of this experience and interaction with patients allowed her to build on her own philosophies and ideas about psychotherapy and analysis. She has built up a large following in relation to "play" and the relationship between internal and external influences regarding neurosis. "In the playing of the child and in the words and dream images of the adult are clues not only about what has gone wrong but about what I believe to be the ubiquitous reparative intent — the wish to make things better... Interpretations are, in my view, best conjointly made by patient and analyst, not pronounced by the analyst in ways that connote authority or finality, since that would discourage using the interpretations as playthings." Sanville has worked very hard on her notion of playing and playthings, having written a book on its importance in therapy, entitled The Playground of Psychoanalytic Therapy. As Arnold Levin says in his review of her book, "Sanville's love affair with language makes her writing eminently readable, but does not blind her or us to its limitations in the affective interactions between people, especially those engaged in the psychotherapeutic encounter". However, there was slight criticism of her book and its lack of intersubjectivity. Herbert Rabin writes, "[T]here is only cursory mention of Kohut and no use of the rich and powerful intersubjective perspective of Stolerow, Brandchaft, and Atwood... Intersubjective explanations, judiciously added, could enrich and deepen our understandings of Jean Sanville's excellent therapeutic work". On the whole, Sanville's research and work is considered invaluable to the field of psychoanalysis.

In between her writing and research, she lectured at UCLA and was a faculty member as the Los Angeles Institute for Psychoanalytic Studies. From 1974-1976, she served as the President of the Board of Trustees for the Institute of Clinical Social Work (now the Sanville Institute), then Dean of the Institute from 1977-1979.

In her spare time, she has worked as a health consultant for various governments in Latin America (she is fluent in Spanish), the Caribbean, and the Far East. She and her husband also enjoy traveling extensively, in between jobs, to places such as India, Sri Lanka, Mexico, Indonesia, Singapore, and Japan. At present, she resides in Los Angeles.