In reality, there's very little about MacArthur's military career that actually suggests he was a great general.
He got himself a division right before the end of the WWI, thanks in large part to his mother lobbying for him to get one. During the interwar years he was involved in the Bonus Army fiasco, and then just prior to his initial retirement insisted that he be awarded the first Purple Heart. When recalled to active service he was given command of the Philippines, where he then failed to put in practice the very war plans he helped design when Japan attacked Pearl Harbor. He then bugged out (in fairness he was ordered too), but then insisted on getting a Medal of Honor (the citation which he authored himself), while denying it to General Wainwright, who had remained behind with his men and was forced to surrender. He then set up his headquarters in Australia, surrounding himself with Yes Men while spending the rest of the war being a pain in the ass to the Navy. He insisted on re-taking the Philippines, after doing so appointed a Japanese Collaborator to rule because he knew that MacArthur had been given a cash payment from the former Filipino President.
While occupying Japan he washed over the various crimes of the Japanese Emperor, and in Korea he willfully ignored the evidence of the impending Chinese offensive, resulting in a disaster for the UN forces that was averted only after Ridgeway took command. Its no small surprise that after MacArthur returned to the US, calls for him to run for President dropped off considerably once he was allowed to speak freely and everyone realized what an pompous, egotistical jackass he was.
He's not the worst American General (Inchon was clever, and his performance as a field commander was decent), but he was one of the most egregious, and hugely overrated. Someone once told me that it was good that Patton had died in Europe because had he lived he almost certainly would have found himself under MacArthur in Korea, and probably would have fragged the mother****er.