Dana Trier, a retired tax partner at Davis Polk & Wardwell, currently serves as counsel in Davis Polk's tax department in New York City. His practice focuses on domestic and international tax planning for corporate mergers, acquisitions, and spinoffs and on the taxation of financial products and institutions.

Professor Trier rejoined Davis Polk in April 2019 after serving as deputy assistant secretary for tax policy in the U.S. Treasury Department under the Trump administration, where he oversaw the Office of the Tax Legislative Counsel, assisted in establishing and implementing the legislative goals of the Office of Tax Policy, and coordinated the administrative guidance projects of the Office. He previously served as the Department's acting deputy assistant secretary for tax policy, tax legislative counsel, and deputy tax legislative counsel from 1988 to 1989 during the administrations of Presidents Ronald Reagan and George H.W. Bush.

Professor Trier has been listed as a leading tax lawyer in several legal industry publications, including Chambers Global; Chambers USA; Practical Law Company’s Cross-Border Tax on Corporate Transactions Handbook; Law Business Research's Who's Who Legal—International Who's Who of Business Lawyers; Euromoney’s Expert Guide to the World's Leading Lawyers—Best of the Best U.S.; Tax Directors Handbook; and American Lawyer Media's Corporate Counsel: Best Lawyers Annual Guide to Tax Law. He previously was chair of the Corporate Tax Committee for the ABA Section of Taxation, and currently serves on the executive committee of the Taxation Section of the New York State Bar Association. Professor Trier also has taught a variety of tax courses at Georgetown University Law Center, Columbia University Law School, and University of Miami Law School, including corporate and partnership taxation, consolidated returns, taxation of property transactions, international taxation, and employee benefits.

He did graduate work in history and international affairs at Princeton University.