--- title: "Mary K. O'Brien | KnowJudges" canonical: "https://knowjudges.com/kyj/judge/mary-k-o-brien" page_type: "judge_profile" updated: "2026-08-22" --- # Mary K. O'Brien Supreme Court of Illinois · Justice ## Profile - Court: Supreme Court of Illinois - State: Illinois - Role: Justice - Service status: active - Last verified: 2026-08-22 ## Summary Official statewide and applicable court procedural guidance applies to this judge. ## Biography ### Professional career - Mary Kay O’Brien is an American judge and politician who has held the role of Justice of the Illinois Supreme Court for the 3rd District since December 5, 2022 - Official site: Illinois Courts – Justice Mary K. O’Brien Office of the Illinois Courts ### Education - University of Illinois College of Law in — J.D. (1994) ### Additional information - In 1996, she was elected to the Illinois House of Representatives for the 75th district, serving from 1997 to 2003. - O’Brien began her legal career at the Grundy County State’s Attorney’s Office before opening her own law firm in Coal City, Illinois. - On the Appellate Court, O’Brien served on multiple commissions and committees, including the Illinois Courts Commission, Illinois Workers Compensation Commission, and the Appellate Court Access to Justice Committee - During her legislative tenure, she chaired the Judiciary II Criminal Law Committee and championed reforms such as expanding the statute of limitations for criminal sexual assault of a minor and requiring psychological evaluations for animal torture cases - She has received numerous awards, including the Star Award from the Kankakee Society of Women in the Law, Zonta Club International Woman of the Year Award (Kankakee Chapter), and the Outstanding Alumni Award from Western Illinois University ## Before you appear - Read the judge-specific standing order first when one is listed. - Check the docket and case orders for requirements that supersede broader guidance. - Confirm current remote-access and courtroom technology arrangements before the proceeding. ## Courtroom Rules ### recording and broadcasting Scope: statewide Photography, broadcasting, and recording in an Illinois courtroom are permitted only under Supreme Court authority or Rule 44's stated exceptions; participants may not record a remote proceeding unless the court directs it or extended-media coverage is approved. Evidence excerpt: the taking of photographs in the courtroom during sessions of the court or recesses between proceedings and the broadcasting or televising of court proceedings are permitted only to the extent authorized by order of the Supreme Court [Illinois Supreme Court Rule 44, Photography and Video in the Courtroom](https://ilcourtsaudio.blob.core.windows.net/antilles-resources/resources/8db700cb-c17a-421d-8fdc-95ad22b399c9/Rule%2044.pdf) Source checked: 2026-07-26 ### official record Scope: statewide The official record may be taken stenographically or through a Supreme Court-approved electronic recording system, including approved videoconferencing services. Evidence excerpt: The record of court proceedings may be taken by stenographic means or by an electronic recording system, including video conferencing services, approved by the Supreme Court. [Illinois Supreme Court Rule 46, Official Record of Court Proceedings](https://ilcourtsaudio.blob.core.windows.net/antilles-resources/resources/24ad75b6-a0a0-4a9f-b44e-1cf4daa67820/Rule%2046.pdf) Source checked: 2026-07-26 ## Sources - [Official profile](https://www.illinoiscourts.gov/courts/supreme-court/meet-the-justices/) - [Official roster](https://www.illinoiscourts.gov/courts/supreme-court/meet-the-justices/) - [Illinois Courts official judicial roster](https://www.illinoiscourts.gov/courts/supreme-court/meet-the-justices/) - [Illinois Supreme Court Rule 44, Photography and Video in the Courtroom](https://ilcourtsaudio.blob.core.windows.net/antilles-resources/resources/8db700cb-c17a-421d-8fdc-95ad22b399c9/Rule%2044.pdf) - [Illinois Supreme Court Rule 46, Official Record of Court Proceedings](https://ilcourtsaudio.blob.core.windows.net/antilles-resources/resources/24ad75b6-a0a0-4a9f-b44e-1cf4daa67820/Rule%2046.pdf) - [justice](https://www.illinoiscourts.gov/justice/36/Mary-K-OBrien/justice/) ## JSON-LD ```json { "@context": "https://schema.org", "@graph": [ { "@type": "WebPage", "@id": "https://knowjudges.com/kyj/judge/mary-k-o-brien", "url": "https://knowjudges.com/kyj/judge/mary-k-o-brien", "name": "Mary K. 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