At the start of filming, Gregory Peck disliked General Douglas MacArthur. After filming he changed his mind, understanding the challenges MacArthur had faced. He also stated he believed President Harry S. Truman was wrong to relieve MacArthur of his command in Korea in April 1951.
Although Gregory Peck had reservations about the film's script and production quality, he later called it one of his favorite roles, if not one of his favorite movies.
Gregory Peck had the good fortune of actually naturally bearing a striking resemblance to General Douglas MacArthur. He had some of his hair shaved off since the real MacArthur was quite bald.
One aspect of MacArthur not covered in the film was the general's near-messianic popularity in postwar Japan. MacArthur was beloved by the Japanese for the same reasons that he was hated by Americans: his flair for the dramatic, his insistence on absolute obedience to his orders, and his seven-day-a-week commitment to duty. There were many Japanese who thought MacArthur should live in the Imperial Palace instead of the Emperor.