MacAurther retired from the US Army in 1937 at which time he became a general officer in the Philippine Army, so for a period of time he wasn't serving overseas as an American officer but was serving in a foreign military all together. He was recalled to the American military in 1941 and during the entirety of WWII he served in the pacific. During this time it was fairly common that other senior officers didn't return to the United States either due to the demand of their position. After WWII he was given command of all occupation forces and activities in Japan and of course took command of all UN forces at the start of the Korean War.

Now, at the same time there were two other things which kept him in the east. First transportation and logistics of that era were far more difficult. There existed no aircraft which could fly from the continental US to Japan without stopping. The second was that he had a very contentious relationship with many civilian leaders like Truman as well as many military leaders. MacAurther was know for being impossibly pompous. Indeed by the time of Korea he had taken to making his own policies even when they were contrary to offices US Policies, which is part of what got him removed from command during Korea. So, after WWII he basically had his own little empire in Japan.

TL;DR - 1937-1941 served as an officer in the Philippine Army, 1941-1945 busy with WWII, post-WWII basically became the military ruler of his own little empire.

Hi all, a quick note from the moderators.

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Edit: Since this mod note doesn't seem to have stemmed the tide of poor answers here, I thought I'd do some analysis on the comments so far just for fun.

At this moment, there are 32 removed comments. Those tally up as follows:

• 15, or almost half, are remarks about removed comments. There's no mystery here people: they've been removed because they don't answer the question, and certainly not in any way up to subreddit standards.

• 9 in one thread which starts with an incorrect answer, with resulting questions/objections

• 2 personal anecdotes

• 2 guesses/conjecture

• 2 personal opinions about MacArthur; neither addressing the question

• 1 trying to restate the question

• 1 off-topic example