Joseph H. McMahon is a highly respected and accomplished lawyer who focuses his practice on the areas of business counseling, high-stakes litigation, crisis management, and white-collar crime. Throughout his career, Joe has built a reputation as an elite trial lawyer and a careful and discrete problem solver and advisor to key executives in government, manufacturing, media and private equity. Joe has extensive experience, as an advisor and general counsel to his corporate clients, in complex disputes on both sides of the table, and in “bet-the company” litigation in the areas of healthcare fraud, catastrophic injury, civil rights, as well as high stakes government and regulatory investigations and enforcement.
During his tenure as State’s Attorney for Kane County, Illinois, Joe represented the fifth largest county in Illinois in all matters and led one of the largest prosecutor’s offices in Illinois. As State’s Attorney, Joe oversaw successful investigations and prosecutions in the areas of financial crimes, public corruption, violent crimes, large-scale drug trafficking, homicide, and civil matters in the areas of labor and employment, civil rights, environmental matters, zoning and development and litigation in both state and federal courts. Joe’s diverse background, comprehensive trial experience, coupled with his management abilities, position him as a valuable advocate and trusted advisor to his individual, municipal, and business clients.
In 2016, he was appointed the Special Prosecutor in the investigation and prosecution of former Chicago police officer, Jason Van Dyke for the murder of Laquan McDonald, a case commanding national attention for several years. In that case he served as lead trial attorney in the years’ long investigation and jury trial covered by local, national, and international media groups. WTTW Chicago’s public broadcast television station described the conviction as a “landmark monthlong trial” and the conviction marked the first successful prosecution of a Chicago police officer for murder in approximately 50 years.
Joe’s experience in courtrooms, boardrooms and conducting investigations on sensitive matters makes him especially qualified to conduct internal investigations and guide clients in managing through their most critical crises so executives can get back to running their business.
Joe was the Illinois state director for the National District Attorney’s Association and served on its executive committee where he developed a non-partisan coalition that includes members of Congress, the United States Department of Justice, members of the Illinois General Assembly and state and federal prosecutors across the country. As state’s attorney, he was selected by his peers to serve on the board of directors of the Illinois State’s Attorney’s Appellate Prosecutors and he was chair of the Illinois State’s Attorney’s best practices committee where he led efforts to identify and implement model programs in the areas of diversion, eye-witness identification, prosecutor training and trial practice for prosecutors’ offices across Illinois. As State’s Attorney he served over 500,000 constituents in Northern Illinois, and more broadly served in roles with national reach. He worked closely with the United States Department of Justice (DOJ) in the Northern and Central District of Illinois, the Federal Bureau of Investigation in Chicago and Washington D.C. and the federal joint terrorism task force.
He has extensive private practice experience defending class actions stemming from the Telephone Consumer Protection Act (TCPA), qui-tam claims brought against individual medical professionals, practice groups and health systems under the False Claims Act in healthcare billing, and allegations of consumer and mortgage fraud including those brought by state and federal regulatory agencies. He obtained a verdict in favor of his client, an automobile leasing company against claims of consumer fraud brought by a former member of the Rockettes and served as outside general counsel to a minor league professional sports team. He has served as lead negotiator for his clients and secured non-prosecution agreements, favorable settlements and dismissals for his clients facing regulatory enforcement with draconian statutory damages, exclusionary and debarment provisions.
Mr. McMahon is a co-founder of Griffin Williams McMahon & Walsh, LLP. Before returning to private practice, he was the elected state’s attorney in Kane County, Illinois and previously in private practice as co-founder of McMahon Williams and as a partner in one of the largest national law firms in the United States. He also served as a deputy prosecutor in the Illinois Attorney General’s Office where he led the investigation and prosecution of public corruption and healthcare fraud in government run and administered healthcare programs.
Mr. McMahon is a member of the American Bar Association, the Illinois State Bar Association and is a past chair of both the corporate law departments section council and the corrections and sentencing committee. For more than a decade he served on the judicial evaluation committee outside of Cook County for the Illinois State Bar Association.
Mr. McMahon has been an instructor for the Northeast Multi-Regional Training Institute (NEMRT) for state and federal law enforcement officers and was the coordinator for the Illinois Attorney General’s Trial Advocacy Program from 2000-2001.
Community Involvement & Awards
Joe has served on the not-for-profit board of directors, including as chair, of Fox Valley Hospice (now Hands of Hope) the largest volunteer hospice organization in the United States and the City of Elgin’s Parks and Recreation advisory board. He has been formally recognized for his commitment and support of civil rights, mental health services and public safety by numerous organizations including the City of Aurora, the Alliance Against Intoxicated Motorists, Family Services Association of Greater Elgin Area, the Community Crisis Center, the Quad County Urban League, the Illinois States Attorneys Association and Fight Crime, Invest in Kids.