Patrick W. Pearsall


Patrick has decades of experience representing Fortune 500 companies and sovereign states in complex commercial contract and investment disputes.

In addition to his commercial work, Patrick is often also called upon to assist companies and executives struggling with exposure from a geopolitical crisis. Patrick is widely recognized as one of the foremost experts in the world on investment protection and dispute avoidance. He has successfully resolved claims involving billions of dollars for clients in dozens of industries.

For nearly a decade, Patrick served in the U.S. State Department working on economic diplomacy. He departed in 2017 as the Chief of Investment Arbitration.
In addition to his representations, Patrick was on a drafting committee for revision of the ICC Rules, was advisor on the revision of the AAA Rules, and led the negotiations of several bilateral and multilateral treaties on behalf of the United States.

Patrick has received several awards and serves on multiple boards. He is band ranked in Chambers, recommended in the Legal 500, listed in Latinvex as a "Top 100 Lawyer" in 2024, and the youngest person ever listed as a "Global Thought Leader" the highest designation in the peer ranked Who' s Who Legal: Arbitration, where he is recognized as "an incredible advocate," "whose razor-sharp mind is unmatched" and who is a "leader in public international law."

He is an adjunct professor at Columbia Law School and Georgetown University Law Center where he teaches two courses on arbitration. He has also taught at Harvard Law School and Yale Law School.

Patrick sits on the panel of arbitrators for the International Center for Settlement of Investment Disputes (ICSID) as well as for the Hong Kong International Arbitration Centre (HKIAC), the Korean Commercial Arbitration Board (KCAB).

Published Work

Patrick is an absolute rock star of Public International Law. He has an intelligence, experience and bearing that would be impressive in a lawyer nearing the end of his career. To see it in one who is just hitting his peak performing years is rare and special



Registered Foreign Lawyer, England and Wales, 2024

Admitted: District of Columbia Bar, 2009

Admitted: Bar of the State of New York, 2006


J.D., Law, Columbia University School of Law, 2005

B.A., English and Political Science, magna cum laude, Columbia College, 2002

A&O Shearman was formed on May 1, 2024 by the combination of Shearman & Sterling LLP and Allen & Overy LLP and their respective affiliates (the legacy firms). Any matters referred to above may include matters undertaken by one or more of the legacy firms rather than A&O Shearman.