Mr. Masterson’s practice focuses on the areas of Litigation, Energy and Natural Resources, Governmental Relations, Transactional Matters, and Corporate and Non-Profit Governance.

Beginning with a return to his hometown of Casper after graduation from the University of Wyoming’s College of Law, Mr. Masterson worked for County and District Courts in Natrona County, performing legal research for judges, drafting opinions and decision letters and assisting the court in hearings and jury trials. Following his one-year term, Mr. Masterson began three years of private practice focusing on oil and gas law, criminal defense and domestic relations.

In 1990, Mr. Masterson became an Assistant District Attorney in Casper, with extensive experience in the prosecution and litigation of narcotics cases, domestic violence offenses, sexual assault and child exploitation. 1995 found Mr. Masterson in the United States Attorney’s Office for the District of Wyoming, primarily responsible for the enforcement of computer crimes and crimes against children, but also prosecuting the entire spectrum of federal criminal offenses from large, multi-defendant narcotics conspiracies, to gun crimes and bank robberies to immigration offenses and wildlife crimes. During this time, Mr. Masterson was also responsible for the training of federal and state law enforcement officers in substantive issues of law as well as interrogation, detention and search and seizure

In 2003, Mr. Masterson was tapped by Wyoming’s newly elected Governor, Dave Freudenthal, to be the legal counsel and federal/state relations coordinator within the Governor’s Office. For two and a half years, Mr. Masterson performed the daily legal work for the Governor and his office, participated in policy making, inter-agency cooperation, drafting legislation and testifying before legislative and Congressional committees. Mr. Masterson served as the Governor’s representative for state, regional and national organizations including the Western Governors Association, the National Governors Association and the University of Wyoming Board of Trustees. For approximately six months, he served as an Interim Director of the Governor’s Planning Office.

In his final months of service to the state, Mr. Masterson was the Deputy Director of Wyoming’s Office of State Lands and Investments, participating directly in policy making, oversight and administration of over 3.5 million acres of state surface lands and 4.2 million acres of minerals. This role led Mr. Masterson to directly participate in negotiating, legal review and contract drafting of precedent setting state land transactions.

On returning to his hometown of Casper, Mr. Masterson joined former Wyoming Governor and United States Ambassador to Ireland Mike Sullivan in the Wyoming office of Rothgerber Johnson & Lyons LLP.  There Mr. Masterson reentered the private practice of law, serving and representing public and private clients by providing transactional work, legislative and governmental relations, arbitration, and complex litigation in state and federal courts.

Mr. Masterson is an active participant in the Casper community, serving on the board of six non-profits, benefitting health care, education, private grant making and young people.  His volunteer service also extends to the Wyoming State Bar, where he is the Chairman of the Board of Law Examiners as well as the Bar's current President.  He also operates a family-owned ranching company and an oil and gas company.

Mr. Masterson has extensive trial experience in federal and state courts, as well as numerous appearances before permitting, administrative and legislative hearing bodies. His appellate experience includes the Wyoming Supreme Court and the Tenth Circuit Court of Appeals


  • Northern Laramie Range Foundation, et al., v. Converse County Board of County Commissioners, and Wasatch Wind Intermountain, LLC d/b/a Pioneer Windpark I, LLC, and Pioneer Windpark II, LLC, 2012 WY 158, December 14, 2012
  • Exxon Mobil Corporation v. Wyoming Oil and Gas Conservation Commission and Denbury Onshore, LLC, 2013 WY 32, March 15, 2013
  • Powder River Basin Resource Council, et al. v. Wyoming Oil and Gas Conservation Commission and Halliburton Energy Services, Inc., 2014 WY 37, March 12, 2014
  • Hedquist v. City of Casper, et al., 14-CV-045-J, U.S. District Court for the District of Wyoming
    • Selected for inclusion in The Best Lawyers in America© in the fields of Energy Law, 2017-2020, Natural Resources Law, 2018-2020, Appellate Practice, 2018-2020 and Litigation-Real Estate, 2016-2020
    • Selected as a Mountain States Super Lawyer, 2016-2019
    • Recognized in the 2013-2019 editions of Chambers USA Annual Client’s Guide to Business Lawyers in the area of Litigation: General Commercial
    • Author, Beware The Budget Footnote, Wyoming Business Report, February 7, 2016
    • Quoted in Governor Mead Updating Energy Strategy, Wyoming Busines Report, October 6, 2015
    • Author, “Will the State’s Energy Plan Impact My Business?” Wyoming Business Report, August 7, 2015
    • Author, “How Setback Legislation Could Impact Wyoming Businesses,” Wyoming Business Report, February 6, 2015
    • Author, “Wyoming Supreme Court decision on fracking leaves much to speculation,” Wyoming Business Report, June 6, 2014
    • Lecturer and Judge, Wyoming Summer Trial Institute, Laramie, WY, August 2013-2015
    • Author: “Wasatch Wind Prevails in Wyoming Supreme Court Decision on Permitting,” RJ&L Alert, January 2013

* Per Wyoming Rule of Professional Conduct 7.1 (c), the descriptions of our fields of practice do not state or imply certification, specialization or expertise in any particular area of law, unless the description specifically states that the particular lawyer holds a certification or other expertise recognized by the applicable State Bar or regulatory authority.

John A. Masterson

PHONE: +1 307 234 6907

FAX: +1 307 234 6908

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  • J.D., University of Wyoming College of Law, 1986
  • College of Literature, Science and the Arts, University of Michigan, 1983

  • Wyoming, 1986*
  • Wyoming Supreme Court, 1986
  • Wyoming State Judicial District Courts, 1986
  • U. S. District Court, Wyoming, 1986
  • U. S. Court of Appeals, Tenth Circuit, 1987

  • Legislative Liaison to Wyoming Governor Matt Mead, 2012
  • Governor Matt Mead, Transition Team Member, 2010
  • Wyoming State Bar, President (2016-2017)
  • Wyoming State Bar, Member
  • Wyoming Board of Law Examiners, Chairman
  • South Spring Creek Ranch LLC, Manager
  • Laramide, LLC, Manager
  • Independent Petroleum Association of Mountain States, Member
  • Wyoming Medical Center Board Chairman
  • Tate Foundation, Treasurer
  • Natrona County Library Foundation, Board Vice President
  • Drum Corps International, Board Member
  • Troopers Drum & Bugle Corps, Inc., Board Member
  • Troopers Foundation, Board President
  • Rotary International, Member