MacArthur was reared on army posts and attended military school in Texas. At West Point he achieved an outstanding scholastic record, and after graduation (1903) he served in the Philippines and in Japan. He was (1906–7) aide to President Theodore Roosevelt, a friend of his father, and was attached (1913–17) to the army general staff. After the United States entered World War I he fought in France, first as chief of staff of the 42d (Rainbow) Division and then, having been promoted (June, 1918) to brigadier general, as commander of the 84th Infantry Brigade.
As superintendent of West Point (1919–22) he helped modernize the academy's military training program. After holding various commands (1922–25) in the Philippines, he returned to the United States and served (1925) on the court-martial of Gen. William Mitchell. He was (1928–30) department commander in the Philippines and then served (1930–35) as chief of the general staff. In 1932 he provoked much criticism by personally commanding the troop action that evicted the Bonus Marchers from Washington. In the tense and threatening days of Japanese expansion President Franklin Delano Roosevelt appointed (1935) MacArthur head of the American military mission to the new Philippine Commonwealth. Accepting command of the Philippine military establishment, he retired (1937) from the U.S. army, but later returned to duty (July, 1941) to command U.S. armed forces in East Asia.