Judge John Mahoney


Upon election to the bench I was assigned to the First Municipal District, Traffic Division and assigned to hear cases involving traffic enforcement. In July of 2015 I was transferred to the Fifth Municipal District hears cases involving traffic enforcement orders of protection, stalking/civil no contact orders, misdemeanor criminal proceedings, felony preliminary hearings, ordinance and traffic enforcement, marriage and civil union court.


Cook County State’s Attorney’s Office
Public Corruption and Financial Crimes Unit
Mortgage Fraud Unit
Intellectual Property Crimes Unit
Insurance Fraud Unit


I have developed and conducted the investigation and prosecution of hundreds of complex financial crimes and public corruption cases. These cases have involved millions of dollars in losses and a broad spectrum of legal and regulatory issues, including: fraudulent schemes involving insurance companies; complex schemes involving financial institutions such as banks, consumer credit card companies, credit unions, savings and loan associations; corporate embezzlement; money laundering; financial identity theft; wire fraud; forgeries; conspiracy and racketeering; computer fraud; asset location and forfeiture; product counterfeiting; fraud and theft arising from private and public contracts; contracting fraud; bid rigging, bid rotating and bid stringing; bribery, kickbacks and criminal conflicts of interest.

I manage the day-to-day investigative and prosecutorial operations of the unit that is comprised of 20 attorneys, 6 investigators, 4 law clerks and administrative staff. My unit regularly coordinates its activities with numerous outside investigative agencies including the U.S. Postal Inspection Service, U.S. Secret Service, Federal Bureau of Investigation, Bureau of Alcohol, Tobacco and Firearms, Internal Revenue Service, and the Chicago Police Department’s Money Laundering, Organized Crime, Internal Affairs and Financial Crimes Units. I also directly participate in the selection, training, and development of the professional staff in our office.

I have also functioned as the spokesman for Cook County on the Chicago Board of Education Capital Development Task Force, the Northeastern Illinois Identity Theft Task Force and the multi-jurisdictional Mortgage Fraud Task Force.

Peoples Energy Corporation

As in-house corporate counsel, I my practice was primarily devoted to regulatory litigation and legislative activities. In this capacity, I handled over 100 hearings before the Illinois Commerce Commission in cases involving actions under the Public Utilities Act brought by residential, commercial, industrial and contract carriage customers. In addition, I practiced before the Illinois Circuit Court, Chancery Division, defending against TRO petitions, interfaced with the Illinois Commerce Commission during compliance audits relating to 83 Ill.Admin.Code Part 280 (credit, collection and eligibility for service), handled administrative hearings involving gas pipeline safety investigations, and coordinated numerous investigations with the National Transportation Safety Board, Gas Pipeline Safety Division (Jan. 17, 1991 River West Pipeline Incident, 1994 Waukegan and South Champlain Incidents).

I was also responsible for obtaining the regulatory approval of a $50 million municipal bond refinancing, various real estate matters related to retired pipeline rights of way and utility easements, and certain environmental and remediation disputes involving the Illinois Commerce Commission, Illinois Environmental Protection Agency and the Federal Environmental Protection Agency. Throughout my tenure in this position, I routinely delivered needs assessments, research result and investigative strategies to corporate decision-makers. Another significant component of my in-house practice involved various legislative activities, including drafting lobbyists’ position papers for distribution to lawmakers on issues of importance to the utility and extensive participation in highly contested rulemaking rewrites.

Cook County State’s Attorney’s Office
Assistant States’ Attorney

I began my career in the Criminal Appeals Division where I drafted approximately 30 appellate briefs and argued 7 cases before the Illinois Appellate Court and 2 cases before the Illinois Supreme Court. Shortly thereafter, I was promoted to the Juvenile Justice Bureau where I handled delinquency, abuse and neglect cases in connection with the Delinquency Repeat Offender Program. I was then promoted to the Felony Review Unit, where I later returned as a Team Supervisor in 1990. Thereafter, I was promoted to the Grand Jury Homicide/Sex Unit where I handled exclusively homicide and violent sexual offense cases. In 1987, I was the first in my class to be promoted to the Felony Trial Division, where I tried 34 jury trials to verdict (32 wins, 0 losses, 2 hung) and conducted more than 500 bench trials and evidentiary hearings.


DePaul University, B.A. 1981 Cum Laude

IIT/Chicago-Kent College of Law, J.D. 1984

Download Judge Mahoney’s Resume