About

Jack Costello has spent his entire legal career in public service. He has spent thousands of hours in courtrooms – in every part of our county - representing the People of the State of Illinois as a prosecutor. He has tried a wide spectrum of cases - from DUIs to homicides - in hundreds of bench trials and dozens of jury trials. Over the last several years, Jack has worked primarily on complex financial crimes and public corruption, teaming with local, state, and federal authorities against scams affecting thousands of people. He has also been a member of the Anti-Semitic Hate Crimes Task Force since its inception.

In addition to practicing law, Jack has participated in teaching for the National District Attorney's Association and spoken at national conferences regarding intellectual property law. He has also served as a guest lecturer for law classes at DePaul College of Law, teaching the importance of ethics for prosecutors.

Jack is a lifelong resident of Cook County. He grew up in Arlington Heights and attended St. Viator High School, the University of Illinois, and DePaul College of Law. He is deeply involved in activities in the Northwest Suburbs, and he and his wife – also an attorney – raise their children in Arlington Heights.

Jack helped create - and now coaches - the award-winning Rolling Meadows High School mock trial team, and he has previously served as a guest lecturer about the criminal justice system for Barrington High School, Rolling Meadows High School, and Palatine High School. In 2022, District 214 recognized Jack's efforts by awarding him the Distinguished Service Award. Jack has acted as a judge for the Northwest Suburban Bar Association mock trial competition, as well as in various mock trial competitions at UIC John Marshall Law School. He is actively involved in mentoring lawyers and law students of diverse backgrounds. Beyond practicing law, he previously served as a Board Member of the Arlington Heights Historical Society and volunteered at the Arlington Heights Farmers Market helping to bring healthy, sustainable foods to the community.

As a young lawyer, Jack was deeply impacted by a judge who started every morning's court call by emphasizing the need for members of the legal community to treat everyone with courtesy, dignity, and respect. Jack has worked to apply these principles throughout his career.

Jack’s legal acumen, courtroom skills, and commitment to equal justice are respected by Judges, prosecutors and defense attorneys. Working in diverse areas throughout Cook County, Jack is committed to ensuring that vulnerable communities are protected and that everyone, regardless of background or income, has equal access to justice.