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John Lemaster has a diverse litigation practice encompassing the issues vital to business, such as commercial litigation and managing and trying complex cases.

His practice has emphasized condemnation and real property, water rights, NEPA and environmental issues, and business disputes. In addition, John handles insurance coverage and bad faith litigation matters, asbestos defense, and other complex litigation. John’s broad base of experience has given him the opportunity to try a number of jury and non-jury trials, arbitrations, and other evidentiary disputes, and to use many alternative dispute resolution mechanisms to resolve litigation when appropriate.

John has extensive litigation experience in resolving disputes for businesses ranging from breach of contract claims and defense of products liability claims, to claims arising from industrial accidents and operations, to claims arising from corporate transactions and real estate deals. Other cases have involved franchise issues, copyright and trademark and patent issues, antitrust issues, and trade secrets. John has been involved in corporate and partnership disputes, board and trustee disputes, class actions and collective actions, Ponzi schemes, and fraud. John’s practice has included litigating multi-party cases, multi-jurisdictions cases, and multi-suit cases.

John represents clients in water related litigation including general adjudications both in federal and state courts. This includes representation a client in a Federal lawsuit against a state engineer for violations of substantive and procedural due process.

John represents clients’ interests in environmental suits under NEPA both before the Interior Board of Land Appeals and in Federal Court. John has represented clients in CERCLA and RCRA litigation. He defends companies in toxic tort cases and product liability cases.


J.D., magna cum laude, Arizona State University, Tempe, Arizona, 1987, Order of the Coif
B.A., cum laude, Arizona State University, Tempe, Arizona, 1983


AV Preeminent Peer Review Rated by Martindale-Hubbell

Named among Arizona’s Finest Lawyers

Named among The Best Lawyers in America® for Commercial Litigation (2008-2024) by Best Lawyers

Named among Southwest Super Lawyers by Thomson Reuters (2010-2024)

Named among AZ Business Magazine’s Top 100 Lawyers in Arizona (2021)


American Bar Association

Maricopa County Bar Association

State Bar of Arizona, Former Public Relations Committee Member

Litigation Counsel of America, Fellow

State Bar Licenses

Arizona, Colorado

Court Admissions

U.S. District Ct., District of Arizona
U.S. Court of Appeals, 9th Circuit
U.S. Supreme Court


Speaking Engagements:

  • “Legal Holds and Defensible Destructions,” In-House CLE, January 2020
  • “Artificial Intelligence and the Legal Profession: Ethical Issues,” ABA Techshow, March 2019
  • “Artificial Intelligence and the Legal Profession: Embracing the Possibilities,” Association of Corporate Counsel Arizona Chapter, February 2019
  • Recent Developments in E-Discovery,” Arizona Attorney General’s Office, Civil Enforcement Division, April 2018