Mona Sue Weissmark was born in Vineland, New Jersey. She received her bachelor’s degree at McGill University and she received her doctorate degree at the University of Pennsylvania. After earning her doctorate degree, she moved to Cambridge, Massachusetts and completed a three-year postdoctoral fellowship in the Department of Psychology at Harvard University. Subsequently, Weissmark was a lecturer on the faculty of the Harvard University Medical School where she taught graduate courses on research methods.

During the years she taught at Harvard, she received letters of commendation from the dean for her distinguished teaching performance. Weissmark also spent a year at the University of Connecticut in Storrs as a visiting assistant professor. Weissmark moved to Chicago and joined the faculty at Roosevelt University as a tenured associate professor of psychology and she also joined the Department of Psychology at Northwestern University as a visiting scholar.

In 2004 Weissmark joined Northwestern University as a visiting associate professor of psychology, and has remained on faculty in the Department of Psychology.  At Northwestern, Weissmark teaches the undergraduate course, “Psychology of Diversity” and conducts research on the psychology of justice and on the links between memory transmission, transformation and politcial processes.

Weissmark is a clinical and social psychologist. Much of her initial research in graduate school was in clinical psychology. She published numerous journal articles on the mechanisms of psychotherapy. One outlined a theory of how therapists think in action. Another explored the linkages between theory and practice.

But starting in her postdoctoral fellowship at Harvard, she cultivated an interest in studying the empirical predictors of psychotherapy effectiveness. Brendan Maher, then the chair of psychology at Harvard University, met with Weissmark every week for 18 months to develop the study's design and methodology. Subsequently, Weissmark headed the Harvard Psychotherapy Research Project. Weissmark wrote Doing Psychotherapy Effectively published by the University of Chicago Press. The book was a summary of her empirical research on how therapy works.  It presented a tool for measuring therapeutic effectiveness and understanding human transformation.

Weissmark’s postgraduate training in Harvard’s Psychology Department also piqued a long sustained interest in the psychology of justice, and this topic eventually took over her research activities. For the past fifteen years her research has focused on the relational impact of injustice.

Weissmark’s parents were Holocaust survivors, and her own life experiences and professional choices have been indelibly marked by that legacy. Weissmark hypothesized that, while legal systems offered a structured means for redressing injustice, they have rarely addressed the emotional pain, which, left unresolved, is then passed along to the next generation – leading to entrenched group tension and conflict. To test this hypothesis, Weissmark pioneered a first-of-its kind social experiment. She set up meetings between children of Holocaust survivors and children of Nazis. 

Several years later, Weissmark organized another notable meeting between descendants of African American slaves and slave-owners. These face-to-face meetings were videotaped and later transcribed. Weissmark wrote several papers that analyzed the discussions between the children of Holocaust survivors and children of Nazis using the statistical method of lag sequential analysis. The findings documented the way in which a past injustice impacts relational communication, which in turn fosters group tension and conflict. Weissmark's love for research and teaching is balanced by two other deep concerns, for generating knowledge through real-world research, and for giving something back to society by doing research that is easily appreciated by the public.

So in 1995 Weissmark wrote a proposal to establish an Institute for Social Justice. In 1999 a generous gift was received to establish the Institute for Social Justice. As founder and director of the Institute, Weissmark has overseen a comprehensive academic planning process to guide a professional program for social justice studies. She worked to develop an integrated program of curriculum, research, and training focused on social justice.  She also worked to strengthen the administrative and financial base of the Institute for Social Justice (proposal). 

In 2004 Weissmark wrote Justice Matters: Legacies of the Holocaust an World War II published by Oxford University Press. Justice Matters presented the culmination of her theoretical and empirical work on the psychology of justice. The book presented a new framework for understanding how emotions and cognitions follow perception of an injustice. It illustrated how the psychology of hatred and ethnic resentment is passed from generation to generation. And it provided insights into the aftermath of ethnic and religious conflicts around the world, from Rwanda to the Balkans, from Northern Ireland to the Middle East.

Weissmark’s distinguished research has received wide critical acclaim. Besides the national and international magazine publications in which her work featured, including Psychology Today, Ms., Harvard Magazine, Jerusalem Report, the Jewish Federation News, She Magazine, and the Chrismon Magazine, her work received coverage in the New York Times, the Chicago Tribune, the Chicago Sun Times, the Frankfurter Allgemeine Zeitung, and the Guardian. Weissmark’s work was also featured on many radio and TV shows, including National Public Radio’s All things Considered, the BBC, the CBS Sunday Morning News, and NBC Dateline. Most recently Weissmark’s book Justice Matter was made into a documentary television film that aired nationwide on WDR German television. The film Seeing the Other Side -- 60 years after Buchenwald  was produced by Johanna Holzhauer of WDR German Television. The film has been distributed to schools and churches throughout Germany.

Weissmark lives in Evanston, IL with her husband, Daniel Giacomo, a Northwestern University psychiatrist. They have an eleven-year-old daughter.