John F. Mahon, Jr.

John Mahon


Email | (314) 345-5094
Karen Leabig | (314) 345-5068
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  • Saint Louis University School of Law, J.D., 2004
    • Editor, Saint Louis University Law Journal
  • Boston College, B.A., magna cum laude 2001
  • King’s College, University of London, England 1999




John Mahon is a trial lawyer who has earned the respect of his clients and colleagues as a skilled and knowledgeable attorney, primarily concentrating on defending medical negligence, product liability and other personal injury lawsuits, as well as insurance coverage and litigation matters.  John is valued for his work ethic and thoughtful approaches to problem-solving.

John is active in local and national bar associations and regularly lectures to nursing students on legal issues. He also chairs the firm’s Business Development Committee.


  • Recognized as one of The Best Lawyers in America in the area of Product Liability Litigation Defense (2016-2018) and Insurance Law (2018)
  • Martindale-Hubbell AV Preeminent Peer Review Rating for Litigation, Medical Malpractice and Personal Injury
  • Missouri and Kansas Super Lawyers Rising Star (2010-2017)
  • “Up & Coming Lawyer”, Missouri Lawyers Weekly (2011)
  • Recieved a “Top Plaintiff Verdict or Settlement” in 2009 and a “Top Defense Verdict” in 2007 as reported by Missouri Lawyers Weekly
  • Best Oral Advocate, Bar Association of Metropolitan St. Louis Young Lawyers’ Division Inaugural Trial Advocacy Competition (February 2007)


  • Speaker, “Legal Issues for Health Care Providers,” Student Nurse Association, St. Louis Community College-Forest Park campus (April 2017, September 2015, September 2014)
  • Speaker, “Legal Issues for Health Care Providers,” Fundamentals of Nursing, St. Louis Community College-Meramec Campus (November 2014)
  • Speaker, “Legal Issues for Health Care Providers,” Practical Nursing/Respiratory Therapy Programs, St. Louis College of Health Careers (November 2014, May 2014, October 2013, November 2017)
  • Speaker, “Legal Issues for Nurses,” Trends Nursing Program, Jefferson College School of Health Professionals (April 2012)
  • Speaker, “Construction Fraud,” Associated General Contractors of St. Louis Fraud Detection Prevention Seminar (July 2010)
  • Speaker, “They Took What? Information Employers Need to Know About Computer Tampering Laws,” CLE Presentation for Client (June 2009)

Professional Affiliations

  • The Theodore McMillian American Inn of Court at Saint Louis University School of Law
    • Barrister (2014 – 2017)
  • The Lawyers Association of St. Louis
    • Executive Committee (2009 – 2013)
  • St. Louis Association of Healthcare Risk Managers
  • Defense Research Institute
  • St. Louis County Bar Association
  • Bar Association of Metropolitan St. Louis


  • Advisory Board for the St. Louis College of Health Careers
  • Young Friends Steering Committee – Saint Louis Art Museum
  • Saint Louis University High School Alumni Board

Bar Admissions

  • United States District Courts
    • Eastern and Western Districts of Missouri
    • Southern District of Illinois
  • Missouri
  • Illinois