Anita L. Allen, also known as Anita Lafrance Allen-Castellitto, was born in Fort Worden (Port Townsend, Washington) in 1953. Her parents, Carrye Mae Allen (née Cloud) and Grover Cleveland Allen were both natives of Atlanta, Georgia. Allen's father made a career in the United States Army, serving in both the Korean War and the Vietnam War. Her father was a member of "Operation Kapers," a squad of enlisted men who entertained combat soldiers in Korea with song, dance and comedy. Allen spent her childhood living on military bases, including Fort Benning, Georgia and Schofield Barracks, Hawaii.

Allen was one of six children. Her brother, Michael Patrick Allen, began working as an environmental lawyer for Microsoft in 2008. Other siblings are Cynthia Ann Allen Jackson and Monica Lynne Allen Newell, both of whom have worked for the federal government, Newell for the Centers for Disease Control; Grover Cleveland Allen, Jr, a professional engineer employed by the GE corporation; and Andre Ramon Allen, who made a career as a Master Sergeant in the United States Air Force and later became a paralegal.

In 1985, Allen married Paul Vincent Castellitto, a lawyer from New Rochelle, New York who specialized in white collar criminal defense law. The pair adopted two children. An earlier marriage in 1982 to artist Michael Kelly Williams of Detroit, Michigan ended in divorce. Allen was the model for William's woodcut, "Afternoon of a Georgia Faun," which began as a collage of the same name. An original version of the woodcut was printed at the acclaimed Printmaking Workshop of Robert Blackburn and now resides in the permanent print collection of the Library of Congress in Washington, D.C.

In 2006, Allen became an elder of the Bryn Mawr Presbyterian Church.

Allen's experiences and perspectives have been profiled in a number of books, including Laurel Holliday’s, Children of the Dream (2000), Ellis Cose's, The Rage of a Privileged Class (1994), George Yancy's African American Philosophers: 17 Conversations (1998) and Elwood Watson: Outsiders Within (2008). She was featured in Carlin Romano's article, “A Challenge for Philosophy." Of her, he writes, "Penn’s Anita Allen is at the top of her field, but she has serious concerns about its lack of openness and diversity," Philadelphia Inquirer, October 24, 2007.

Allen graduated an honor student from Baker High School in Columbus, Georgia in 1970 in just three years. Allen holds a B.A. from New College of Florida, on whose board of trustees she later served. Allen has twice delivered the commencement address at New College. While enrolled at New College, Allen spent a year studying in Italy and Germany. Under the direction of Professor Bryan Norton, she completed an undergraduate thesis on the philosophy of logical positivist Rudolf Carnap. Allen received her M.A. and Ph.D. in philosophy from the University of Michigan. Allen received a rigorous training in analytic philosophy at the University of Michigan, where she also studied modern dance, alongside classmate Madonna. Professor Richard Brandt, a noted proponent of moral utilitarianism, advised Allen's doctoral thesis, "Rights, Children and Education." Her dissertation examined Thomas Hobbes' and John Locke's theories of parental authority, and the moral ideal of a right to education. She argued for greater autonomy for children. Allen was one of the first African American women to earn a PhD in Philosophy, along with Joyce Mitchell Cook, LaVerne Shelton, and Adrian Piper. She is the first African American woman in history to hold both a J.D. and Ph.D. in philosophy. Allen received her J.D. from Harvard Law School. While attending Harvard Allen served as a teaching fellow for Professors Michael Sandel, Ronald Dworkin, Robert Nozick and Sissela Bok. She worked as a summer law Associate at the Gaston Snow Ely Bartlett law firm in Boston and at Milbank, Tweed, Hadley & McCloy in New York.

Prior to joining the Penn faculty, Allen was professor and associate dean for research and scholarship at Georgetown University Law Center from 1987 to 1998, and an assistant professor of philosophy at Carnegie-Mellon University from 1978 to 1981. She was the first African American woman to serve on the faculty of the University of Pittsburgh School of Law, 1985 to 1987. She has been a visiting faculty member at Waseda University Law School in Tokyo, Johns Hopkins School of Public Health, University of Washington, Hofstra Law School, University of Arizona College of Law, Princeton University, Yale Law School, Villanova University School of Law, and Harvard Law School.

Allen is an expert on privacy law and contemporary ethics. She is also recognized for scholarship about legal philosophy, women’s rights, and race relations.

She has received fellowships from Princeton’s Program in Law and Public Affairs, the American Council of Learned Societies, the American Association of University Women, and the Ford Foundation.

Allen is a member of the Pennsylvania and New York bars. She briefly practiced law with Cravath, Swaine & Moore in New York City in 1984 and 1985.

Allen serves on the board of directors of several charities and professional associations, including the American Association for Practical and Professional Ethics, the Electronic Privacy Information Center, the Hastings Center, the Maternity Care Coalition, the National Association for Women Lawyer’s Judicial Evaluation Committee and the West Philadelphia Alliance for Children. She was a member of the National Advisory Committee for Human Genome Research.

Allen has been invited to lecture at colleges and universities across the United States and in Canada, Europe, Australia, Japan and Taiwan. She has appeared on The Ethical Edge, 20/20, Nightline, Good Morning America, 60 Minutes, Face the Nation, Talk of the Nation and other television and radio programs. She has written for the popular press, including O, the Oprah magazine; the Daily Beast.com, and the Newark Star Ledger.