Woodrum was elected as a Democrat to the Sixty-eighth Congress and re-elected eleven times. He served from March 4, 1923, until his resignation on October 24, 1945 (effective December 31, 1945), to become president of the American Plant Food Council, Inc. Considered a "Southern Progressive" in Washington, Woodrum bucked the powerful Senators Carter Glass and Harry F. Byrd and the Byrd Organization to become an ardent "New Dealer." As a member of the United States House Committee on Appropriations, he steered federal money for the purchase of land for Roanoke's airport, originally called "Woodrum's Field" in his honor, and today known as the Roanoke–Blacksburg Regional Airport. He was also instrumental in bringing the United States Department of Veterans Affairs hospital, now known as the Salem Veterans Affairs Medical Center to his district. The hospital brought many jobs to the region during the Great Depression.