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Williams Kastner Member

Heidi L. Mandt

Heidi L. MandtMember
Bar Admissions




U.S. Court of Appeals
9th Circuit

U.S. District Court
Eastern District of Washington
Western District of Washington

Heidi L. Mandt


Heidi Mandt is a litigator defending clients in product liability, medical and other malpractice/professional liability claims, and toxic torts. Her practice covers general insurance defense and insurance coverage matters as well. She has tried more than twenty cases to verdict in both state and federal courts ranging from product liability to personal injury and commercial claims.
In addition, Heidi has significant experience handling complex matters, including construction liability and breach of contract claims, catastrophic personal injury and death cases, and first- and third-party insurance claims. Her experience and success in the courtroom has established her as a leader in major cases with high monetary exposure.

As such, she has regularly defended individuals, retail establishments, construction companies, automotive and commercial truck manufacturers and chemical companies in personal injury and product liability claims, as well as companies involved in commercial disputes.

Professional Experience

  • Williams Kastner Greene and Markley, Of Counsel | 2017 – Present


  • Member, International Association of Defense Counsel
    • Membership Committee
    • 2018 Mid-Year Meeting CLE Steering Committee
  • Volunteer, The Leukemia & Lymphoma Society
    • Former Member, Board of Directors, OSWIM Chapter; Coach, Captain & Mentor, Team in Training Program
  • Member, Oregon State Bar
  • Litigation Section

Recognitions & Awards

  • The Best Lawyers in America©
    • Product Liability Litigation – Defendants, 2019, 2020
  • Named as a “Rising Star” in Oregon Super Lawyers
    • General Litigation, 2008


Willamette University
College of Law, J.D., 1995

Washington State University
B.S., Psychology, cum laude, 1990

Presentations & Seminars

  • Speaker, “When is a Claim Not a Claim? To Disclose or Not to Disclose: The Lethal “Knowledge of Circumstances; and, The “Interrelated Wrongful Acts” Provision: 6 Degrees of Separation,” USLAW Professional Liability Exchange, Jersey City, NJ, May 2018.
  • Speaker, “Ensuring Your Work Product Remains Your Own in Hiring and Working with Experts,” Oregon Association of Defense Counsel (OADC) Annual Convention, 2015.