American newspaper editor and publisher, popularly known as Colonel McCormick, whose idiosyncratic editorials made him the personification of conservative journalism in the United States. Under his direction the Chicago Tribune achieved the largest circulation among American standard-sized newspapers and led the world in newspaper advertising revenue.

A grandnephew of the inventor Cyrus Hall McCormick and grandson of Joseph Medill (Medill, Joseph), editor and publisher of the Chicago Tribune (1855–99), McCormick served as a Chicago alderman (1904–05) and as president of the Chicago Sanitary District Board (1905–10). As an officer with the American Expeditionary Force in France during World War I, he was awarded the Distinguished Service Medal.

McCormick was named president of the Chicago Tribune Company in 1911, and he shared the functions of editor in chief and publisher with his cousin Joseph Medill Patterson from 1914 until 1925, when he became sole editor and publisher. McCormick acquired or established forestlands, paper mills, hydroelectric installations, and shipping companies (all to supply the Tribune with newsprint) as well as radio and television facilities and additional newspapers: the tabloid New York Daily News (1919, directed solely by Patterson from 1925); and the Washington Times-Herald (1949, sold to the Washington Post 1954).

A strident if rather idiosyncratic conservative, McCormick attacked Prohibition, the New Deal administration of President Franklin D. Roosevelt, the Fair Deal of President Harry S. Truman, and the Marshall Plan for European recovery after World War II.