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Daniel T. Hartnett

Of Counsel
fax +1 312.517.7579

Daniel Hartnett represents individuals and entities in federal criminal investigations and prosecutions involving the FBI, IRS, SEC, HHS, USDA, FDA, and Postal Inspection Service and related enforcement actions in parallel civil suits and administrative proceedings.

Dan’s practice focuses on audits, summons enforcement proceedings, prepayment judicial review in the U.S. Tax Court, and refund litigation in federal district courts. He also regularly represents accountants, attorneys, physicians, and other professionals before licensing authorities.

Dan has broad experience conducting corporate internal investigations and providing counsel and crisis communication to general counsel, senior management, and boards of directors. Prior to entering private practice, Dan served as a Trial Attorney in the Tax Division of the U.S. Department of Justice, Office of Special Litigation (1984-1986) and Criminal Section (1982-1984). He also served as a Captain in the United States Army Judge Advocate General’s Corps (1978-1982).


J.D., Loyola University Chicago School of Law, Chicago, Illinois, 1977
B.A., University of Notre Dame, Notre Dame, Indiana, 1974


Named among The Best Lawyers in America® for Criminal Defense: White-Collar by Best Lawyers (2024)

Named a Leading Lawyer in Chicago by Leading Lawyers℠ (2004 – 2024)


American Bar Association, Tax Section (1986 – present)

Committee on Civil and Criminal Tax Penalties



State Bar Licenses


Court Admissions

U.S. District Ct., N.D. of Illinois
U.S. District Ct., N.D. of Illinois Trial Bar
U.S. Tax Court
U.S. Court of Appeals, 5th Circuit
U.S. Court of Appeals, 7th Circuit
U.S. Court of Appeals, 8th Circuit
U.S. Court of Appeals, 11th Circuit
U.S. Supreme Court
U.S. Court of Military Appeals
U.S. Court of Appeals, District of Columbia Circuit

Representative Experience

Circuit Courts of Appeal

  • Represented an individual in successful challenge to applicability of the bid-rigging enhancement.
  • Represented an Estate in appeal of Tax Court judgment regarding apportionment of the marital deduction.
  • Represented meat producer in dispute over entity’s right to receive USDA inspection services following conviction of principal.

U.S. District Courts

  • Represented an individual in criminal insider trading prosecution and parallel SEC civil proceeding.
  • Represented a physician in criminal prosecution for conspiracy to accept kickbacks for patient referrals.
  • Represented skilled nursing facilities and therapy provider in civil suit alleging violations of the False Claims Act.
  • Represented an individual in criminal investigation and prosecution for under-reporting revenue of a closely-held corporation.
  • Represented individual in proceedings to challenge IRS summons based on Fifth Amendment assertion.
  • Served as expert witness for law firm responding to IRS summons for client files.
  • Represented sales representatives in grand jury investigation involving unauthorized sales of diagnostic devices.
  • Represented medical supplies sales representative connection with claimed kickback payments.

U.S. Tax Court

  • Reasonable compensation deduction. Represented an entity concerning its entitlement to deduction for amounts paid to principal owner.