What was Douglas MacArthur's role in World WarII?

Answer 1

MacArthur was the General of the Pacific fleet Navy during WWII. He led a southern attack against Japan that began just above Australia and eventually captured every Japanese occupied islands except the mainland.

According to B. H. Liddell Hart's History of the Second World War (Da Capo Press paperback edition 1971, Page 346) "At the beginning of April (1942) the United States had assumed responsibility for the whole Pacific area, except Sumatra, While the British would remain responsible for Sumatra and the Indian Ocean area." ... The American sphere was divided in two -- the South-west Pacific under General MacArthur, whose headquarters were now established in Australia and the Pacific Ocean area under Admiral Chester W. Nimitz. Both were strong and forceful men, likely to clash. The Japanese plan provided ample call on, and scope for, the activity of each. Moreover the borderline between their respective spheres came in the Solomon Islands, where the Japanese amphibious threat required the conjoint use of MacArthur's ground forces and Nimitz's naval forces."

As this quote indicates, MacArthur was not General of the Pacific fleet. He was an Army officer commanding the U.S. ground and non-naval air forces primarily responsible for the destruction of Japanese ground forces scattered on the many Pacific island locations. Whether all of these were captured by the General is best discussed under a topic directly related to that aspect of the war including those islands initially bypassed. The U.S. Pacific fleet including its naval aviation forces (as well as coordination with the British Pacific fleet) were under the overall command of Admiral Chester Nimitz.