An Act (52 Stat. 351; 5 U. S. Code, Sec. 87a) approved May 13, 1938, made the 11th of November in each year a legal holiday—a day to be dedicated to the cause of world peace and to be thereafter celebrated and known as "Armistice Day." Armistice Day was primarily a day set aside to honor veterans of World War I, but in 1954, after World War II had required the greatest mobilization of soldiers, sailors, Marines and airmen in the Nation’s history; after American forces had fought aggression in Korea, the 83rd Congress, at the urging of the veterans service organizations, amended the Act of 1938 by striking out the word "Armistice" and inserting in its place the word "Veterans."
With the approval of this legislation (Public Law 380) on June 1, 1954, November 11th became a day to honor American veterans of all wars.
Later that same year, on October 8th, President Dwight D. Eisenhower issued the first "Veterans Day Proclamation" which stated: "In order to insure proper and widespread observance of this anniversary, all veterans, all veterans' organizations, and the entire citizenry will wish to join hands in the common purpose. Toward this end, I am designating the Administrator of Veterans' Affairs as Chairman of a Veterans Day National Committee, which shall include such other persons as the Chairman may select, and which will coordinate at the national level necessary planning for the observance. I am also requesting the heads of all departments and agencies of the Executive branch of the Government to assist the National Committee in every way possible."
For the complete history, please go to the U.S. Department of Veterans Affairs: http://www.va.gov/opa/vetsday/vetdayhistory.asp.