MacArthur's career begins with his graduation, with the highest honors, from West Point in 1903. During World War One, MacArthur commanded the 42nd "Rainbow" Division of the Allied Expeditionary Force in France. His command was distinguished and he was wounded. After the War, MacArthur was superintendant of West Point, from 1919-1922. In January of 1930 he was promoted to full general (4 stars) and named the U.S. Army's Chief of Staff.

MacArthur retired from the Army in 1937, one year after the President of the Phillipines, Manuel Quezon, appointed him Field Marshall of the Phillipine Army. In 1941 MacArthur was recalled to active duty as the U.S. prepared to enter World War Two. By 1942 MacArthur was Supreme Allied commander of the Southwest Pacific theater. In 1942 he was, like his father before him, awarded the Medal of Honor. In January of 1945, MacArthur was promoted to the rank of five-star general. On September 2, 1945 on board the USS Missouri in Tokyo Bay, MacArthur accepted Japan's unconditional surrender.

In June 1950, with the beginning of the Korean War, MacArthur was appointed the Supreme United Nations commander. However, on April 11, 1951 he was relieved of his command by President Truman. MacArthur, always brash, had publically disagreed with the politicians.

There was an unsuccessful attempt to get MacArthur to run for the Presidency in 1952. He spent the last 12 years of his life living in New York City speaking out on public issues and advising government officials.