As the Committee's policy director Warren was responsible for developing policy in all areas within the Committee's jurisdiction. Major legislation that Warren worked to enact into law includes the Tax Increase Prevention Act, the ABLE Act, the Middle Class Tax Relief and Job Creation Act, two highway and infrastructure funding bills in 2012 and 2014, and free trade agreements with Colombia, Peru, Panama and South Korea. In addition, Warren was responsible for the development and introduction of the first detailed legislation since 1986 to comprehensively reform the US Tax Code with the introduction of the Tax Reform Act of 2014. Other major pieces of legislation developed by the Committee during Warren's tenure as policy director include the Bipartisan Congressional Trade Priorities Act of 2014 and the SGR Repeal and Provider Payment Modernization Act.
Warren served as a senior staffer to both the National Commission on Fiscal Responsibility and the Joint Select Committee on Deficit Reduction. In his role as Policy Director, Warren was responsible for working with Subcommittee Staff Directors to develop and implement the Committee's priorities and coordinated those efforts with House of Representative Leadership-serving as a key liaison with the Administration, the Senate as well as House Leadership. Originally, Warren served as one of the Committee's primary economists focused on trade policy, where he crafted the economic analysis behind the recent trade agreements with Colombia, Panama, Peru, and South Korea.
Before joining the Ways and Means Committee, Warren served as an economic advisor and international trade analyst at the US International Trade Commission. He also consulted on international trade and tax issues at Economic Consulting Services.