headshot of John P Shanahan

John P. Shanahan

Milwaukee, Partner

headshot of John P Shanahan


  • Marquette University Law School (J.D., 2012)
  • University of Wisconsin - Madison (B.S., 2009)

Bar Admissions

  • State of Florida
  • State of Wisconsin
  • U.S. District Court for the Eastern District of Wisconsin
  • U.S. District Court for the Western District of Wisconsin
  • U.S. District Court for the Northern District of Illinois
  • U.S. District Court for the Southern District of Florida
  • U.S. District Court for the Northern District of Florida
  • U.S. District Court for the Middle District of Florida


  • Recognized as “One to Watch” by The Best Lawyers in America© publication (2022-2024)
  • Recognized as a “Rising Star” in Business Litigation and Construction Litigation by Wisconsin Super Lawyers® (2020-2023)
  • Recognized as a “Rising Star in Law” by BizTimes (2022)


John Shanahan is a trial attorney with over a decade of experience litigating complex corporate cases in state and federal courts across the country. Mr. Shanahan focuses on complex business disputes, construction defect litigation, intellectual property cases, and has significant experience addressing e-discovery issues. Additionally, Mr. Shanahan is highly experienced in handling the unique legal and factual issues involved with defending significant trucking accident cases.


Part of trial team that handled multi-million dollar arbitration involving complex contract dispute between billion dollar U.S. corporations, including analysis of the application of the Uniform Commercial Code in light of his client’s obligations to provide a substantial amount of goods as well as services under the contract. Achieved defense victory, recovery on counterclaim, and recovery of attorney’s fees following three years of litigation and twelve-day trial. Specific terms of the arbitration proceedings and final award are subject to a confidentiality agreement.

Member of trial team that successfully defeated all claims alleged against a national manufacturing company in a multi-day bench trial in Illinois state court. The case involved complex issues regarding warranties under the Uniform Commercial Code.​

Member of litigation team for Lac du Flambeau Band of Lake Superior Chippewa Indians and tribal casino in multi-party dispute over $50,000,000 bond transaction. The case spanned eight years in multiple courts (U.S. District Court for the Western District of Wisconsin, Case Nos. 09-CV-768, 12-CV-255, and 13-CV-372; Lac du Flambeau Tribal Court, Case No. 13-CV-115; Seventh Circuit Court of Appeals Case Nos. 10-2069, 14-2150, and 14-2287; and Wisconsin Circuit Court, Waukesha County, Case Nos. 12-CV-187 and 15-CV-302) before settling under terms favorable to Mr. Shanahan’s clients.​

Member of team that successfully defended one of the Unnamed Movants in the State’s John Doe Investigation that was recently halted and declared unconstitutional by the Supreme Court of Wisconsin.