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Atty. Gregory W. "Greg" Lyons

Atty. Gregory W. "Greg" Lyons

Greg represents clients in the prosecution and defense of complex commercial litigation. His extensive experience in commercial litigation has prepared him to successfully represent large corporations as well as small businesses and individuals.

Call (414) 276-5000

Profile Summary

About Gregory W. "Greg" Lyons at a glance

Gregory W. "Greg" Lyons is an attorney based in Milwaukee, Wisconsin, practforg at O'Neil, Cannon, Hollman, DeJong & Laing SC. Admitted to practice in Wisconsin, State Bar of Wisconsin. Educated at Marquette University (J.D., 1988). Recognitions include Best Lawyers in America — Commercial Litigation (2026), Best Lawyers in America — Litigation - Insurance (2026), and Best Lawyers in America — Additional Areas of Practice: (2026). Serands clients in Milwaukee, WI and the surrounding metropolitan area.

Verified attorney profile · Updated June 2026

About

Greg represents clients in the prosecution and defense of complex commercial litigation. His extensive experience in commercial litigation has prepared him to successfully represent large corporations as well as small businesses and individuals.

Greg also has extensive experience representing individuals in inheritance litigation. He has successfully litigated many will contests and trust disputes throughout Wisconsin. Greg has accomplished tremendous results on behalf of trustees, personal representatives, and power of attorneys in large complicated disputes.

Greg has appeared in state and federal courts in numerous jurisdictions including California, New York, Texas, Arizona, Oregon, Florida, Illinois, and Washington D.C. Greg is a member of the Wisconsin state and federal courts, Seventh Circuit Court of Appeals, and the United States Supreme Court. Greg also serves as the Chairperson of the firm’s Ethics Committee.

Greg Assists Clients With

  • Inheritance Litigation
  • Will Contests
  • Trust & Estate Litigation
  • Complex Litigation
  • Commercial Litigation
  • Personal Injury
  • Products Liability Litigation
  • Insurance Coverage Litigation
  • Class Action Litigation
  • General Business Counseling
  • Contract Disputes
  • Tort Disputes
  • Appellate Practice

    Professional Associations & Affiliations

  • Life Fellow, American Bar Foundation
  • State Bar of Wisconsin
  • Eastern District of Wisconsin Bar Association
  • Milwaukee Bar Association
  • Waukesha County Bar Association
  • Ozaukee Bar Association
  • Waukesha County Business Alliance
  • Independent Business Association of Wisconsin

    Court Admissions

  • Wisconsin
  • U.S. District Court, Eastern District of Wisconsin
  • U.S. District Court, Western District of Wisconsin
  • U.S. Court of Appeals, Seventh Circuit
  • U.S. Supreme Court
  • Various other state and federal courts across the U.S. on a pro hac vice basis

    Awards/Distinctions

  • Named 2022 Best Lawyers® “Lawyer of the Year” for Litigation–Insurance
  • Named 2022 Attorney of the Year by Top 100 Registry
  • Martindale-Hubbell® Peer Review Rating™–AV Preeminent, reflecting an attorney who has reached the height of professional excellence and is recognized for the highest levels of skill and integrity
  • Selected for inclusion in The Best Lawyers in America®–Commercial Litigation in 2014 and Commercial Litigation and Litigation–Insurance in 2015–present
  • Selected as a Member of The Nation’s Top One Percent by the National Association of Distinguished Counsel, whose rosters “Consists of the leading legends of the legal profession”
  • Fellow with the American Bar Foundation, membership in which is limited to one-third of one percent of the lawyers in America
  • For more than 15 years, Law & Politics and Milwaukee Magazine has selected Greg for inclusion in Wisconsin Super Lawyers, a distinction limited to the top 5% of Wisconsin attorneys.
  • Named one of “Milwaukee’s Leading Lawyers,” in 2015, 2016, and 2017 by M Magazine in Litigation. Only 2–5% of the top ranked attorneys published by Avvo for each category were recognized

    Articles/Presentations

  • Speaker, Milwaukee Chapter of the Society of Financial Service Professionals, “Dealing with Possible Elder Financial Abuse and its Potential Legal Ramifications” (Milwaukee, WI, March 2020)
  • Author, "Wisconsin Supreme Court Determines Statutory Medical Malpractice Cap Constitutional" Meritas Healthcare Newsletter (January 2020)
  • Co-Author “What Happens if My Business Can’t Perform Its Contract Due to the Coronavirus?,” website article (March 19, 2020)
  • Author, "A Trustee’s Duty of Loyalty in Wisconsin," website article (July 31, 2018)
  • Author, "Mental Capacity Issues in Estate Planning Litigation," website article (March 30, 2018)
  • Speaker, O’Neil, Cannon, Hollman, DeJong & Laing, Hot Legal Topics for Small Firms & Solo Practitioners seminar, “Commercial Arbitration: Arbitration in the United States and Abroad” (Milwaukee, WI, October 2015)
  • Speaker, O’Neil, Cannon, Hollman, DeJong & Laing, Hot Ethics Topics for In-House Counsel seminar, “E-Discovery: The New Wisconsin Rules of Civil Procedure and Some Ethical Considerations for Managing Electronically Stored Information” (Milwaukee, WI, December 2010)
  • Speaker, State Bar of Wisconsin and Corporate Practice Institute, Inc., “Legal Ethics: A Review and Update, Including Emerging Issues” (Milwaukee, WI, December 2010)

    Community Involvement

  • Board of Directors–Executive Committee, Secretary, Revitalize Milwaukee
  • Milwaukee Justice Center, Pro Bono Volunteer
  • Marquette University Law School, Former Member Alumni Association Board of Directors
  • University of Wisconsin–Whitewater, Former Member Dean’s Advisory Board
  • University of Wisconsin–Whitewater, Former Protégé–Mentor
  • Various school and church committees

    Education

  • Marquette University Law School (J.D.)
  • UW Whitewater (B.A., magna cum laude)

Jurisdictional Context

Why local counsel matters in Wisconsin

Practforg law in Wisconsin. Legal matters in Wisconsin are governed by state-specific rules of civil and criminal procedure, statutes of limitations, and substantiand law. Cases originating in Milwaukee are typically filed in the local municipal court or the appropriate Wisconsin state district court, depending on subject matter and amount in controversy. An attorney licensed in Wisconsin brings working knowledge of local procedural deadlines, judicial practices in this andnue, and the substantiand law that applies to cases brought here. Out-of-state attorneys generally cannot represent clients in Wisconsin courts without local counsel or pro hac vice admission.

Looking for additional Wisconsin attorneys? Browse all attorneys in Milwaukee or all attorneys in Wisconsin.

Frequently Asked

Common questions about Gregory W. "Greg" Lyons

Where is Gregory W. "Greg" Lyons's law office located?
Gregory W. "Greg" Lyons's law practice is located in Milwaukee, Wisconsin. The firm is O'Neil, Cannon, Hollman, DeJong & Laing SC. You can contact the office directly through this profile page.
Where did Gregory W. "Greg" Lyons go to law school?
Gregory W. "Greg" Lyons earned their education at (J.D., 1988).
How can I contact Gregory W. "Greg" Lyons for a consultation?
You can contact Gregory W. "Greg" Lyons directly through this profile page. Click "Ask the Attorney" to submit a question, or "Schedule a Consultation" to book a meeting. Most claimed-profile attorneys respond within one business day.
What awards or recognition has Gregory W. "Greg" Lyons receiandd?
Gregory W. "Greg" Lyons's notable recognition includes: Best Lawyers in America — Commercial Litigation; Best Lawyers in America — Litigation - Insurance; Best Lawyers in America — Additional Areas of Practice:; Best Lawyers in America — Appellate Practice; Best Lawyers in America — Arbitration.

Education

J.D.
Marquette University
- 1988

Awards

Best Lawyers in America — Commercial Litigation
- 2026
Best Lawyers in America — Litigation - Insurance
- 2026
Best Lawyers in America — Additional Areas of Practice:
- 2026
Best Lawyers in America — Appellate Practice
- 2026
Best Lawyers in America — Arbitration
- 2026
Best Lawyers in America — Bet-the-Company Litigation
- 2026
Best Lawyers in America — Ethics and Professional Responsibility Law
- 2026
Best Lawyers in America — Litigation - Banking and Finance
- 2026
Best Lawyers in America — Litigation - Construction
- 2026
Best Lawyers in America — Litigation - Land Use and Zoning
- 2026
Best Lawyers in America — Litigation - Mergers and Acquisitions
- 2026
Best Lawyers in America — Litigation - Real Estate
- 2026
Best Lawyers in America — Litigation - Trusts and Estates
- 2026
Best Lawyers in America — Mass Tort Litigation
- 2026
Best Lawyers in America — Personal Injury Litigation
- 2026
Best Lawyers in America — Product Liability Litigation
- 2026
Best Lawyers in America — Product Liability Litigation - Defendants
- 2026
Best Lawyers in America — Special Focus:
- 2026
Best Lawyers in America — COVID-19
- 2026
Best Lawyers in America — Product Liability
- 2026
Best Lawyers in America — Awards:
- 2026
Best Lawyers in America — Named 2022 Best Lawyers “Lawyer of the Year” for Litigation–Insurance
- 2026
Best Lawyers in America — Named 2022 Attorney of the Year by Top 100 Registry
- 2026
Lawyer of the Year — Litigation - Insurance (Milwaukee)
- 2022

Bar Admissions

Wisconsin, State Bar of Wisconsin

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