John J. D'AttomoJohn J. D'Attomo

John J. D'Attomo

Of Counsel




John is a highly-skilled and accomplished litigator.  During more than 25 years of practice, John has first-chaired trials to jury verdict in complex civil litigation matters, as well as briefed and argued appeals before the Illinois Appellate Court, the Illinois Supreme Court, and the U.S. Circuit Court of Appeals.  Judges, lawyers, and clients have praised John for his trial and appellate advocacy skills.  John’s meticulous preparation, skill, and tenacity have achieved highly favorable results for his clients.  His quiet confidence and authenticity win over juries.  John's prior experience includes more than 13 years practicing with a large law firm, including five years as a partner.  Prior to entering private practice, John served for two years as a federal judicial law clerk for Judge John M. Roll in the U.S. District Court for the District of Arizona.  He is licensed to practice in Illinois and Arizona (currently inactive).

Business and Commercial Litigation
John regularly represents individuals and businesses in disputes involving claims of breach of contract, unfair competition, trade secret misappropriation, fraud, and breach of fiduciary duty.  John’s experience includes disputes between shareholders and between LLC members, as well as a broad array of disputes between corporate clients and their suppliers, vendors, customers, and former employees.   In a recent trial, John obtained a judgment for a manufacturer-client on claims of alter ego liability, breach of fiduciary duty, and fraudulent transfer, including a 6-figure award of attorney fees.  In another case, John won a defense verdict for a manufacturer-client following a 5-day jury trial defeating a supplier’s claim for wrongful termination of a supplier agreement.  John also has substantial experience in bankruptcy litigation matters having served as litigation counsel to a Chapter 11 Trustee in more than 30 adversary proceedings.

Real Estate Litigation
John handles a wide range of commercial and residential condominium association legal matters including foreclosures, condemnation proceedings, and other issues arising under condominium Declarations, Bylaws, and Rules and Regulations.  In a matter of first impression, John successfully persuaded the Illinois Appellate Court to recognize an “implied right of action” in favor of his purchaser-clients to redress the seller’s failure to disclose a rental restriction governing the condominium unit.  In another matter, John won a substantial judgment for a real estate developer following a jury trial arising from a lender’s breach of a loan commitment. In another jury trial, John obtained a highly-favorable settlement for a real estate developer and luxury home builder in a construction defect case.  (The case settled mid-trial following John’s cross-examination of the opponent’s expert witness.) John also litigates commercial and residential foreclosure cases, mechanic’s liens, and commercial landlord-tenant disputes.

Health Care Litigation
John has prosecuted and defended antitrust claims between competing health plans, between hospitals and physicians, and between hospital systems.  He has also litigated matters involving the suspension or revocation of physician staff privileges, as well as disputes arising from physician peer review proceedings.  John was lead trial counsel in a five-day trial of the only-known case involving the suspension of physician clinical privileges tried to a jury in Illinois.  Additionally, John was one of the lead trial attorneys representing a non-profit hospital before the Illinois Department of Revenue following the unprecedented revocation of its tax-exempt status.

Employment Litigation
John counsels businesses and employees concerning the enforceability of non-compete and non-solicitation agreements and, where necessary, litigates these matters in court proceedings.  He has both successfully prosecuted and defended claims of employment discrimination before the Equal Employment Opportunity Commission (EEOC) and the Illinois Department of Human Rights.

Probate Litigation
John represents executors, trustees, administrators, and beneficiaries in contested proceedings including will contests, petitions to remove executors and trustees, and actions seeking to recover assets rightfully belonging to the estate.  In other cases, John has represented beneficiaries, heirs, and family members challenging the distribution of a decedent’s assets as well as the propriety of estate inventories and accountings.

Published Works:

Condo Officers and Directors Beware, 112 Ill. B.J. 36 (July 2024)

Hospital Must Report Voluntary Surrender of Privileges to the NPDB Notwithstanding Potential Invalidity of Underlying Action, BNA Health Law Reporter, 24 HLR 1444 (Nov. 5, 2015).

Litigating The Suspension of Physician Clinical Privileges: The Intersection Of The Illinois Medical Studies Act And The Rule of "At Issue" Waiver, ISBA Health Care Law Section Newsletter (June 2012)

Court Reverses $33 Million Damages Award In Favor of Suspended Cardiologist On Grounds Of Peer Review Immunity, Drinker Biddle Health Law Beat (Spring 2009)

Negligent Credentialing: Illinois The Latest State To Recognize The Tort, Drinker Biddle Health Law Beat (Spring 2009)

Wireless Communications Provider Defeats Vendor's Claim for $1 Million Arising From Blanket Purchase Order, Drinker Biddle Client Alert (Feb. 2009)

The "Buyer's Option" Contract in Illinois, 96 Ill. B.J. 418 (Aug. 2008)

Recovering Damages For Wrongfully Issued Injunctions in Illinois, 92 Ill. B.J. 34 (Jan. 2004)

Health Insurer Defeats Attempted Monopolization Claim, BlueCross BlueShield Association Legal Affairs Bulletin (Feb. 2002)

South Dakota Case Will Be Significant Precedent For Hospital Governing Boards To Take Economic Factors Into Consideration When Granting Medical Staff Privileges, Gardner Carton & Douglas Client Memorandum (Jan. 2001)

Practice Areas


  • John Marshall Law School, Chicago, JD, 1993, Cum Laude, Law Review: John Marshall Law Review, 1992 - 1993
  • Loyola University Chicago, BS, Criminal Justice, 1990, Magna Cum Laude


  • Adjunct Instructor, Paralegal Studies – City Colleges of Chicago (2021 – 2023)
  • Life Saving Award – City of Park Ridge Fire Department (2016)
  • The Super Jake Foundation – Secretary and Director (2005 – 2013)
  • Center for Disability and Elder Law – Volunteer Attorney of the Year (2009)