John McArthur established the Law Office of John Burritt McArthur in 2008 in order to combine his active trial docket with a growing practice as an arbitrator.

McArthur has been involved in some of the largest commercial disputes of the last 30 years. In the 1980s, as a partner in Houston's Susman Godfrey LLP, McArthur played a major role in natural gas take-or-pay litigation. In addition, he handled major cases over a furniture distribution network, a defense of an insurance company for refusing to reimburse a novel cancer treatment, and defense of the seller of an offshore drilling rig. And he devoted substantial time to an antitrust lawsuit over tennis ball pricing and another antitrust case between Northrop Corporation and McDonnell-Douglas Aircraft over the F-18 fighter plane.

In the 1990s, McArthur represented one of Alaska's native corporations in a large dispute with the Department of the Interior, advised major oil companies on Alaskan matters, and handled other energy cases while in a mid-career program at Harvard’s Kennedy School of Government and then a Ph.D. program in public policy at the University of California at Berkeley.

From 1999 to 2008, while working for the law firm that ultimately became San Francisco's Hosie McArthur LLP, McArthur devoted the bulk of his time to a gasoline price-fixing case and to a series of oil posted-price and natural gas royalty cases, including cases for the States of Alaska and Louisiana. Since 2008, he has continued to serve as lead trial counsel in complex commercial cases. He provides trial representation for plaintiffs and defendants in high-dollar commercial cases, including for states and other clients in royalty and tax litigation. In addition, McArthur increasingly serves as an arbitrator in large commercial disputes.

McArthur has been a trial lawyer in some of the largest trials of the last few decades. Early in his career, he was one of the lawyers who tried the first take-or-pay case to go to trial on a repudiation theory. The jury awarded a $563 million verdict against El Paso Natural Gas Company in one of the top 10 jury verdicts in 1988. Soon after counsel, including McArthur, argued the appeal in a Houston court of appeals, El Paso settled by paying $302 in cash and returning mineral interests later appraised at $135 million.

McArthur played a major role in a 2004 case that Chevron filed against the State of Louisiana. The State’s case began as a defense case. It was one of the few oil posted-price cases to go to trial. After the court realigned the State as the true plaintiff, the jury awarded $111 million against Chevron in one of the top 15 verdicts in 2004.

In 2012, McArthur served as lead trial counsel for the State of Alaska in successfully defending claims by an independent oil company that would have reallocated six million barrels of oil, with a market value of over $600 million dollars, from the State to various interest owners. For a representative list of other past cases, see Experience.

McArthur represents clients in state and federal courts around the country. He represent plaintiffs and defendants. His clients have ranged from some of the country's largest corporations to small businesses, Alaskan native corporations, States, and individuals,. Among his plaintiff clients have been the states of Hawaii, Alaska, Louisiana, and Mississippi; Aetna Life Insurance; the second largest producer of natural gas in Texas; and one of the largest interstate gas marketers into the California market. Among his defense clients have been Aetna, Sonat Offshore, British Petroleum, BHP Proprietary (U.S.), and BASF.

In terms of subject matter, McArthur's cases have run the gamut of complex commercial cases and involved everything from antitrust and securities disputes to insurance and intellectual property lawsuits, from racketeering and qui tam claims to contract, fiduciary, partnership, joint venture, fraud and other tort disputes. His experience covers many varieties of energy cases.

McArthur has significant academic training, including in the economic concepts surrounding market definition and market power and the measurement of damages. Holding advanced degrees in economics and public administration as well as his law degree, and a Ph.D. in public policy, McArthur has graduate-level training in the economic and financial concepts used in many complex commercial disputes.

McArthur has a broader perspective on complex trial work than many lawyers because he has served as an expert and as an arbitrator as well as a trial lawyer. Among his expert testimony is the testimony cited with approval by the Arkansas Supreme Court in Seeco v. Hales, 22 S.W.3d 157 (Ark. 2003). He has written over 40 articles in law reviews and bar publications, including articles on arbitration, judicial management, energy issues, and antitrust. For his major publications, see Publications.

As an arbitrator, McArthur is listed as a neutral for the Large Complex Case, Commercial Case, Oil and Gas, and National Energy Panels of the American Arbitration Association; as a Distinguished Neutral for the California and Energy, Oil and Gas Panels of the International Institute for Conflict Prevention and Resolution (CPR); as a Public Arbitrator for the Financial Industry Regulatory Authority (FINRA), and by the international arbitration centers of Hong Kong, Dubai, and Kuala Lumpur. He is a Fellow of the Chartered Institute of Arbitrators in London and a listed arbitrator for the London Court of International Arbitration. He is also a member of the International Bar Association and the American Society for International Law, as well as a Sponsoring Member of the Institute for Energy Law and the Institute for Transnational Arbitration. His approach to arbitration is summarized in Arbitration.

McArthur has been acknowledged for his experience by his peers. He has held an "av" rating from Martindale-Hubbell for decades. In 2007, he was elected a Fellow of the Litigation Counsel of America, a fellowship composed of top American lawyers. He is a Co-Founder of the LCA’s International Institute on Environment, Energy, and Natural Resources (IINREEL). He is a member of the Million Dollar Advocates Forum and the Multi-Million Dollar Advocates Forum.