Dilliard began his career at the St. Louis Post-Dispatch in 1927 and was a reporter and editor there until 1938. In 1937, Dilliard wrote a series of articles for the Post-Dispatch "such as might have been written had an experienced newspaper correspondent been present" at the Constitutional Convention. These articles were compiled into a booklet titled "Building the Constitution" and distributed for free to public schools. Over 850,000 copies were in print. In 1938, Dilliard received a Nieman Fellowship to Harvard University. After the one-year program, Dilliard returned to the St. Louis Post-Dispatch as an editor. Dilliard then volunteered with the U.S. Army in 1943. Dilliard worked for the European edition of the Stars and Stripes newspaper and covered the Nuremberg Trials. After World War II ended, Dilliard returned to work for the St. Louis Post-Dispatch. He became editor of the editorial page in 1949. Dilliard wrote articles advocating for the civil rights and civil liberties of many individuals and groups, including George Anastaplo, Ellen Knauff, Jehovah’s Witnesses and communists. Dilliard wrote a series of editorials in 1954 titled “A War to Stay Out Of” arguing against U.S. involvement in what became the Vietnam War. In his career, Dilliard wrote over 10,000 total editorials and was called “the finest journalist to cover the U.S. Supreme Court” by U.S. Supreme Court Justice William O. Douglas. Dilliard stepped down as the St. Louis Post Dispatch editorial page editor in 1957 but continued to work at the newspaper until he retired fully in 1960.
