Strength Through Tenacity

Greg represents clients in the prosecution and defense of complex commercial litigation, insurance coverage, and products liability. His extensive experience in commercial litigation has prepared him to successfully represent large corporations as well as small businesses and individuals. Greg has also served as class counsel in numerous class actions.

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


  • 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


  • 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 2015–2019
  • 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” in 2015, 2016, 2017, and 2018.
  • For more than 10 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

Professional Associations

  • State Bar of Wisconsin
  • Eastern District of Wisconsin Bar Association
  • Milwaukee Bar Association
  • Waukesha County Bar Associaton
  • Ozaukee Bar Association
  • Waukesha County Business Alliance
  • Defense Research Institute
  • Independent Business Association of Wisconsin


  • Speaker, O’Neil, Cannon, Hollman, DeJong & Laing, “Deposition Preparation-Tips on How to Prepare a Non-Expert Witness for Deposition” (Milwaukee, WI, September 2017)
  • 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 Service

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