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O'Connor & Semmerling Law Group, LLC
711 West Grand Avenue
Suite 303
Chicago, IL 60654

Attorney Profile

Stephen O'Connor


Stephen M. O’Connor’s career has focused on representing clients in the best light possible before the courts.  He strongly believes that each individual client has a unique story that needs to be told.  To that end, Mr. O’Connor has contributed research to the Capital Jury Project, an academic study of jury decision-making and behavior in death penalty cases, through the Center for Justice in Capital Cases at DePaul University. He has trained at the Clarence Darrow Death Penalty Defense College's Mitigation Program (Chicago, Illinois) and the Trial Lawyers College's Death Penalty Seminar (Dubois, Wyoming).  

Mr. O’Connor is a founding partner in The Mercury Endeavor, LLC, a mitigation and sentencing advocacy firm.  He has previously clerked for the Juvenile Division of the Public Guardian of Illinois and for the Cook County Public Defender Office’s Felony Trial Division. He has also worked as a volunteer for Cabrini Green Legal Aid Clinic, helping indigent clients with housing and family legal claims.

Contact Information
Phone: 312.981.9084
Fax: 312.929.3136

The John Marshall Law School, Chicago, Illinois (J.D., 2009)

Loyola University, Chicago, Illinois (B.A., Business Administration, 1988)

Bar Admissions

Professional Memberships
American Bar Association
Chicago Bar Association
Illinois Association of Criminal Defense Lawyers
Illinois State Bar Association
National Association of Criminal Defense Lawyers