Mr. Mahoney is a founding partner of Segal McCambridge Singer & Mahoney and has served as the firm's Co-Chairman for the past nine years. He has served in a leadership position for all 30 years of the firm's existence - a period that has seen the firm grow from a four lawyer Chicago firm to over 160 attorneys in seven cities.
Mr. Mahoney is a trial attorney concentrating in the defense of toxic tort and environmental cases. He conducts a national practice and has served as lead counsel at trials in Illinois, Texas, Ohio, Wisconsin, Florida, Kansas, Louisiana, New York, Massachusetts, California and Indiana. He is national trial counsel for defendants named in thousands of asbestos-related cases and has served as national coordinating counsel for several corporations in mass tort litigation. He has been retained as counsel for defendants in state and federal class-action proceedings and participated in the successful dismissal of class-actions involving cellular telephones (brain cancer) and radar guns (leukemia). Mr. Mahoney has substantial experience in electromagnetic field, chemical exposure, mold, benzene, mercury and welding rod litigation. Within the context of his toxic tort practice, he has developed special expertise in epidemiology, medical causation, toxicology, industrial hygiene, risk assessment and biostatistics. Mr. Mahoney also has considerable experience defending general product liability, professional liability, construction, commercial and insurance coverage matters.
In addition to his leadership role at the firm, Mr. Mahoney is active personally and professionally in his community, serving as Board Chairman at two educational institutions, a member of the Chairman's Circle at the Chicago Council of Global Affairs, a member of the Society of Fellows of the Aspen Institute, a member of the Board of Trustees at Writer's Theatre, the Chairman's Council of the National Democratic Institute, and Chairman of the Chicago Committee of Human Rights Watch. He resides in Chicago.
Segal McCambridge Singer & Mahoney, Co-Chairman
Segal McCambridge Singer & Mahoney Executive Committee, Member
Appointed to Federal Asbestos Product Liability Litigation MDL 875 Joint Plaintiff/Defendant Steering Committee, (2006).
- Recognized by National Academy of Jurisprudence (NAJ), formally the American Academy of Trial Attorneys, as one of the Premier 100 Trial Attorneys in Illinois.
- Appointed as member of the Kennedy Center International Committee on the Arts (KCICA)
- Recognized as a 2015 Top Rated Lawyer in Mass Torts by American Lawyer Media and Martindale-Hubbell®
- Selected as a Member of the Nation's Top One Percent by the National Association of Distinguished Counsel
- Martindale-Hubbell AV Preeminent® Peer Review Rated
- Recognized as an Illinois Leading Lawyer (a designation limited to less than 5% of all attorneys licensed to practice law in Illinois), nominated and selected by peers in the legal community (2004-2017)
- Selected for inclusion in the Illinois Super Lawyers list (no more than 5% of lawyers in the state are selected), nominated and selected by peers in the legal community (2005-2017) and named Top Rated Environmental Litigation Attorney in Chicago, IL.
- Alpha Sigma Nu National Jesuit Honor Fraternity
- Aspen Institute Executive Leadership Program (2005)
- Aspen Institute Justice and Law Program (2006)
- Blue Key Honor Fraternity
- Recognized as a Top Rated Lawyer in Insurance Law by American Lawyer Media and Martindale-Hubbell®
- Recognized as a Top Rated Lawyer in Mass Torts by American Lawyer Media and Martindale-Hubbell®
- Recognized as a Top Rated Lawyer in Energy/Environmental by American Lawyer Media and Martindale-Hubbell®
Professional & Civic Involvement
- Chairman's Council - National Democratic Institute
- Litigation Counsel of America, Fellow
- Chicago Committee for Human Rights Watch, Chairman
- Chicago Council on Global Affairs, Chairman's Circle
- Aspen Institute, Society of Fellows
- Writer's Theatre Board of Trustees, Member
- Goodman Theatre Business Council, Member
- Loyola University Foundation, Advisory Board Member
- Chicago Legal Clinic, Member, Board of Directors (2009-2014)
- American Bar Foundation, Fellow (2002-present)
- Chicago Council of Lawyers, Member
- Defense Research Institute, Member
- Chicago Bar Foundation "Investing in Justice" Campaign, Vice Chairman
- Archbishop Quigley Board of Advisers, President (1993-1996)
- Sacred Heart School Board, President (1994-1997)
- National counsel for nine companies in asbestos related litigation (1988-present)
- Defense verdicts in asbestos-related litigation in Illinois, Wisconsin, Indiana, Connecticut, Texas, Kansas, West Virginia, Massachusetts, Ohio and Florida
- National counsel for two companies in silica litigation
- Successfully argued Havner motion in Texas, excluding evidence of chrysotile exposure in evidence of specific causation
- Successfully barred plaintiff's industrial hygiene expert on Daubert grounds in Dallas County Consolidated asbestos hearing
- Obtained summary judgment for cellphone manufacturer in Illinois class action proceedings alleging brain cancer caused by electromagnetic exposure
- Counsel for Illinois Department of Insurance in liquidation proceeds and litigation involving an insolvent insurer
- Co-cousel in 88-day franchise termination trial in Cook County, Illinois
- Segal McCambridge Public Affairs Forum233 S. Wacker Drive, Suite 5500, 9.6.17
- Segal McCambridge Public Affairs Forum233 S. Wacker Drive, Suite 5500, 7.18.17
- Segal McCambridge Public Affairs Forum233 S. Wacker Drive, Suite 5500, 4.25.17
- Segal McCambridge Public Affairs Forum233 S. Wacker, Suite 5500, 3.21.17
- Segal McCambridge Public Affairs Forum233 S. Wacker Drive, Suite 5500, 2.3.17
Perrin Conferences' Asbestos Litigation Conference, "National Trends Driving Asbestos Litigation" (September 12, 2016).
The Chicago Council on Global Affairs, "From War Crimes to Climate Change: Human Rights in 2016: Interview of Kenneth Roth, Executive Director of Human Rights Watch" (May 5, 2016).
The Chicago Council on Global Affairs panel, "Cuba: Hope or Hype in Havana?" Moderator, Chicago, IL (March 30, 2015).
Human Rights and a Just Society 9th Annual Symposium, "Rwanda: Pathway to a Genocide," Nicolas Copernicus University,Torun, Poland (October 12-13, 2014).
Perrin Conferences’ Asbestos Litigation Conference: A National Overview, “National Trends During Asbestos Litigation,” San Francisco, CA (September 8-10, 2014).
American Conference Institute: 17th National Advanced Forum on Asbestos Litigation “Lung Cancer Cases; Medical, Scientific and Trial Issues,” Chicago, Illinois (June 26-27, 2014).
The Chicago Council of Global Affairs, "Cuba Uncensored: Interview of Yoani Sanchez, Gus Hart Fellowship Award Winner" (June 11, 2014).
American Conference Institute's 15th Annual Advanced Forum on Asbestos Claims and Litigation, "Bankruptcy Filings, Confirmations & Estimations and the Transparency Between Bankruptcy Trusts and Tort Litigation," New York, NY (October 7, 2013).
American Conference Institute's 14th Annual Advanced Forum on Asbestos Claims and Litigation, "Bankruptcy Filings, Confirmations & Estimations and the Transparency Between Bankruptcy Trusts and Tort Litigation," Chicago, IL (June 26, 2013).
Perrin Conferences' Cutting Edge Issues in Asbestos Litigation Conference, "The Top Emerging Trends in 2013 Asbestos Litigation," Beverly Hills, CA (March 18, 2013).
American Conference Institute's 13th Annual Advanced Forum on Asbestos Claims and Litigation, "Year in Review: Examining Hot Jurisdictions, Emerging Trends, and What to Expect in 2013 After the Presidential and Congressional Elections," Philadelphia, PA (January 31, 2013).
Perrin Conferences' Emerging Risks On Dual Frontiers: Perspectives on Potential Liabilities in the New Decade, "Emerging Risks - The Perennial Contenders," London, England (April 12-13, 2012).
Perrin Conferences' Cutting-Edge Issues in Asbestos Litigation, "Emerging Trends in Asbestos Litigation - What To Expect in the Litigation in 2012," Beverly Hills, CA (March 1-2, 2012).
"The Arab Spring, Human Rights, and International Law," Human Rights and a Just Society, Nicolaus Copernicus University, Toruń, Poland (October 17, 2011).
Perrin Conferences' Cutting-Edge Issues in Asbestos Litigation, "Asbestos Litigation in 2011 & Beyond - Current & Emerging Trends," Beverly Hills, CA (March 3-4, 2011).
Perrin Conferences' Cutting-Edge Issues in Asbestos Litigation, "Managing Relationships in 2010 Asbestos Litigation," Beverly Hills, CA (February 25, 2010).
Defense Research Institute, Asbestos Medicine Seminar, "Fiber Type and Mesothelioma Causation - Update on Epidemiology and Practice Tips on Developing the Exposure Profile" (November 12-13, 2009).
"Genocide, Human Rights and International Justice: Past, Present and Future," Human Rights and a Just Society, Nicolaus Copernicus University, Toruń, Poland (October 12, 2009).
HB's National Asbestos Litigation Conference, "'Hot' Jurisdictions: California, Illinois, New York, Pennsylvania and Texas" (September 24, 2009).
Mealey's Lead Litigation Conference, Orlando, FL, "Status of the National Litigations and a Look at Their Future" (April 3-4, 2008).
Mealey's 3rd Annual International Asbestos Conference, London, England, "Across the Pond: The Similarities & Differences Between the U.S. and UK Legal Systems" (October 17-18, 2007).
Defense Research Institute, Chicago, IL, "Pre-eminent Lawyers - Superstars of Trial" (September 27-29, 2007).
Defense Research Institute, Asbestos Medicine Seminar, Las Vegas, NV, "Opening Statements in the Low Dose Chrysotile Case" (October 2006).
Defense Research Institute, Asbestos Medicine Seminar, "Catastrophic Damages and Corporate Conduct: A Defense Primer" (November 2004).
Defense Research Institute Damages Seminar, "Ten Corporate Mistakes Leading to Punitive Damages" (2004).
Defense Research Institute, Insurance Coverage and Claims Institute, "Confronting Environmental, Asbestos, Mold and Other Organic Concerns" (2004).
Defense Research Institute, Insurance Coverage and Claims Institute, "Asbestos Litigation and Legislation" (2003).
Mealey's National Asbestos Conference, "Medical Defenses in Asbestos Litigation" (2003).
Defense Research Institute Asbestos Medicine Symposium, "The Chrysotile Defense: Revisited" (2001).
American Bar Association Annual Meeting Presidential Showcase Program, "Tort Reform in the New Millennium" (2001).
Mealey's National Asbestos Conference," Recent Appellate Developments in Asbestos Litigation" (2000).
American Bar Association Annual Meeting, "Corporate Management of Toxic Tort Litigation" (1998).
American Bar Association Annual Meeting, "Environmental Contamination, Litigation Strategies and Bankruptcy Considerations" (1996).
American Bar Association Annual Meeting, "Essentials of Daubert in Practice: The Role of Expert Scientific Proof at Trial" (1997).
American Bar Association National Meeting, "The Case from Hell, Opening Statements for the Defendant in Toxic Tort Litigation" (1995).
Author / EDITOR / CONTRIBUTING AUTHOR
Mahoney, William (2015, December 4). "A Betrayal of our Better Angels," The Huffington Post.
Member, editorial advisory board, Pattern Voir Dire Questions by Susan Broome, Ph.D. (James Publishing, 2011).
"Asbestos Trust: Time for a Decision," Harris Martin's COLUMNS-Asbestos, Volume 5, Number 9 (July 2005).
Midwest Environmental Claims Association, "Class Action and Mass Torts: History and Recent Developments" (1997).
"Toxic and Hazardous Substances and Environmental Law," Annual Survey, Tort and Insurance Law Journal (1992-1996).
American Bar Association National Institute on Toxic Torts, "The Defense of Increased Risk and Fear of Cancer Claims" (1992).
University of Illinois, J.D. (1978)
Loyola University, B.A., Honors Degree, cum laude (1975)
- Illinois, 1978
- Michigan, 1997
- Texas, 1998
- U.S. District Court, Central District of Illinois, 1988
- U.S. District Court, Northern District of Illinois, 1979
- U.S. District Court, Southern District of Illinois, 1989
- U.S. District Court, Northern District of Indiana, 1995
- U.S. District Court, Eastern District of Wisconsin, 1993