Jon Lahn is a partner in the litigation department. His practice focuses on representing companies and individuals in connection with government investigations and other enforcement actions, and in civil litigation that arises out of government investigations and whistle blower claims. Jon has represented and advised companies and individuals in investigations and litigation in a variety of substantive legal areas, including antitrust law, SEC and PCAOB inquiries, the Foreign Corrupt Practices Act and health care fraud/False Claims Act investigations. He has experience advising clients in matters, including antitrust and competition law matters, involving trans-national conduct that implicates the laws of multiple jurisdictions.

Jon also has significant experience in general litigation and bankruptcy litigation. He was a member of the trial team that obtained the largest environmental recovery in United States history—a $5.15 billion settlement from Anadarko Petroleum Company—after prevailing at trial in the U.S. Bankruptcy Court for the Southern District of New York. He also has an active pro bono practice, representing clients in civil rights trials and administrative proceedings relating to prisoner rights and housing discrimination issues.

Jon has been a contributor to numerous publications in the white collar and antitrust fields, including the Seventh Edition of the ABA’s Antitrust Law Developments treatise and the ABA’s guide to sentencing issues in antitrust law. He also lectures as a guest speaker on government investigations and corporate law topics.

Jon is a board member of the Associate Board of the Legal Aid Society, Chicago’s oldest pro bono legal services organization. He is a member of the Antitrust Section of the American Bar Association and a member of the Illinois State Bar Association.


Thought Leadership


Contributor, Antitrust Law Developments (Seventh), Chapter 8: Criminal Enforcement (2012)

Contributor, American Bar Association Antitrust Sentencing Guidelines Handbook (2012)

Author/Presenter, “Is the Seventh Circuit the New Third Circuit?,” Kirkland Antitrust and Competition Institute (2011)

Kirkland & Ellis Client Alert: “United States Attorney General Pledges Unprecedented DOJ Focus on Financial Fraud” (2009) (with J. Eisenberg, M. Filip, C. Clark, M. Garcia and H. DePippo)

“Writing as Remedy: The Possibilities of Court-Generated Narrative in ‘Personal Status Litigation’,” 34 Vermont Law Review 121 (2009)

“The Demise of the Law-Finding Jury and the Birth of American Legal Science,” 57 Cleveland State Law Review 553 (2009)

Note, “The Uses of History in the Supreme Court’s Takings Clause Jurisprudence,” 81 Chicago-Kent Law Review 1233 (2006)

Memberships & Affiliations

Board member, Associate Board of the Legal Aid Society

Member, Antitrust Section of the American Bar Association

Member of the Illinois State Bar Association


Admissions & Qualifications

  • 2007Illinois


  • United States District Court for the Northern District of Illinois2009


  • Polish


  • Illinois Institute of Technology, Chicago-Kent College of LawJ.D.with High Honors2007

    Order of the Coif

    Chicago-Kent Law Review, Executive Notes & Comments Editor, 2006–2007

  • Northwestern UniversityB.A., English2003