Justice Mary Kay O’Brien has been a judge for over 19 years, first on the Third District Appellate Court and most recently as a Justice on the Illinois Supreme Court, having been elected on November 8, 2022, but her commitment to public service began long before her judicial career. As a student at Western Illinois University, O’Brien was elected to represent students on the Student Government Association and advocated for programming on the Committee on Student Activity Fees. Upon graduation, O’Brien worked for the Illinois Attorney General in the Kankakee Regional Office before entering the University of Illinois College of Law in August 1991.
As a new lawyer, Justice O’Brien fine-tuned her advocacy skills helping clients navigate the court system and in 1996 she broadened the reach of her advocacy skills by winning a seat in the Illinois General Assembly. As a state representative, O’Brien worked tirelessly on behalf of working families and crime victims, working to increase the quality and availability of daycare, fought to expand the Family and Medical Leave Act as well as fighting to increase protections for victims of violent crimes. O’Brien chaired the Judiciary II Committee on Criminal Law, reforming the state’s death penalty statutes and also championed reforms in the Grain Insurance Code, opened access to generic drugs for Illinois consumers and served as a taxpayer watchdog on the Illinois Audit Commission. Those experiences lead O’Brien to seek a seat on the appellate court where her mission was to provide a level playing field to all parties to a dispute.
On the appellate court, O’Brien served on numerous committees, including the Supreme Court Rules, Legislative, and Appellate Court Access to Justice Committees, the Illinois Courts’ Commission and the Lawyers Assistance Program. Justice O’Brien recently began her term on the Illinois Supreme Court and will be the Liaison to the Supreme Court Committees on Civil Jury Instruction, Criminal Jury Instruction, Evidence, Juvenile Court and the Lawyers Trust Fund. O’Brien continues to work to increase her understanding of the law and has developed curriculum and helped teach continuing legal education classes. She is active with several bar associations, including the Illinois State Bar Association, the Illinois Judges’ Association and the Women’s Bar Association of Illinois.
Justice O’Brien is involved in her community as a leader with the local 4-H Club, the Essex Community Club, the Kankakee County NAACP, and Ascension St. Mary’s Hospital, where she served as board chair from January 2012 until her election to the Supreme Court. She is a leader for the Illinois Lawyers Assistance Program (LAP), that protects the public from impaired lawyers and judges.
O’Brien and her husband, Todd, are the parents of 3 sons.