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Denis J. Conlon

Of Counsel


130 E. Randolph St.
Suite 3900
Chicago, IL 60601
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Fax: 312.517.7582
J.D., Loyola University Chicago School of Law, Chicago, Illinois, 1961
LL.M., DePaul University College of Law, Chicago, Illinois, 1985, (Taxation)
B.S.C., Loyola University-Chicago, Chicago, Illinois, 1958
State Bar Licenses
Court Admissions
U.S. District Ct., N.D. of Illinois
U.S. District Ct., E.D. of Wisconsin
U.S. District Ct., W.D. of Wisconsin
U.S. Tax Court
U.S. Court of Federal Claims
U.S. Court of Appeals, 7th Circuit

Denis J. Conlon

Of Counsel

Denis J. Conlon is Of Counsel in the Litigation Practice Group in Clark Hill's Chicago office.  Denis has over 50 years of experience litigating cases and counseling clients in federal tax matters, both civil and criminal.  He provides advice and representation in matters requiring detailed knowledge of Internal Revenue Service ruling, examination, appeals, litigation and other IRS procedural matters in the most difficult cases. His experience includes the IRS Industry Specialization Program, primarily exempt organizations, insurance and tax shelters. 
Prior to working at Clark Hill he was of Counsel at Martin, Brown, Sullivan, Roadman, & Hartnett, Ltd., and served in the IRS Office of Chief Counsel as Regional Counsel, Midwest Region and District Counsel, Chicago Office.  He was a Principal at Ernst & Young, LLP as its Director of IRS Controversy, Great Lakes Region.


Co-author of “Tax Court from the IRS Perspective,” a chapter in Federal Civil Tax Practice, published by the Illinois Institute of Continuing Legal Education

Speaking Engagements

Presented on numerous legal subjects for Chicago Bar Association, Federal Bar Association, Ernst & Young, LLP and American Bar Association - Tax Section

Subjects include:

  • Use of Expert Witnesses in Tax Cases
  • Alternative Dispute Procedures in Tax Cases
  • IRS Reorganization of 1998
  • Use of Statistical Sampling in Tax Cases
  • Use of Substance over Form by Taxpayers
  • I.R.C. § 482 Cases in Tax Court
  • Tax Preparer Penalties
Presidential Rank Award, Meritorious Executive - 1991
Secretary of Treasury Award - 1986
IRS Commissioner’s Award - 1992
General Counsel’s Award - Treasury - 1992
Chicago Bar Association
Wisconsin Bar Association
American Bar Association - Tax Section
Adjunct Professor - Chicago Kent College of Law, Tax Crimes and IRS Practice and Procedure
Served as an instructor in the Chief Counsel’s Advance Advocacy School in Williamsburg, Virginia and as lead instructor in Chief Counsel’s Trial Attorney training program in Washington, DC
Served as an instructor for Ernst & Young, LLP in IRS Practice, Insurance Taxation and Exempt Organizations
Served as Co-Chair of IRS Large and Mid-Sized Business, Subcommittee of Tax Section of ABA in 2004
Chairman of Chief Counsel’s Business Review Council
Board Member - Chief Counsel’s Information Management Policy Board
Board Member - IIT Kent Not-for-Profit Conference