Arthur MacArthur IV, son of Douglas MacArthur was born on February 21, 1938 in Manila, Philippines while his famous father, a highly decorated general, was on military assignment with the U.S. Army. At the time of his birth, Douglas MacArthur was already fifty-eight-years old, while his mother, Jean Faircloth MacArthur, was only forty. Douglas MacArthur's son lived in various military locations with his father and mother until 1951 when he first visited the United States.

Little history is known about Douglas MacArthur's son except for the sparse accounts of those who worked closely with Douglas MacArthur during military assignments. Some of those accounts say that the son of Douglas MacArthur was a spoiled child who was often rude to those who were assigned to guard him. According to Harold Tichman, who was a bodyguard for young Arthur and his mother, the child was "a bit of a terror" who kicked several people in the shin, which has been confirmed by other bodyguards. Arthur MacArthur was also said to be a child with a tremendous vocabulary who easily engaged in conversations with adults, but who was also shy around other children. The son of Douglas MacArthur was also a trained pianist who composed music at an early age. Arthur did not show boyish interest in sports or outdoor activities, the most of which consisted of riding his bicycle up and down the long drive from the doors of the American Embassy to the guard post at its entrance. Arthur MacArthur showed a keen interest in animals, often attending the zoo; the story goes that he actually owned a pet goat at one time.

Douglas MacArthur's son had a disengaged relationship with his father, but a very close attachment to his mother. Arthur didn't particularly care for military life, although he respected his father and his accomplishments greatly. Douglas MacArthur wanted his son to follow in the footsteps of his grandfather and namesake, Arthur MacArthur, Sr. and himself, both of whom became extraordinary generals, but rather than go to West Point, the young MacArthur elected to attend Columbia University, where he studied, arts, music and the theatre.

Following his father's death in 1964, it is believed that the son of Douglas MacArthur changed his name to distance himself from the family name, prompting William Manchester, the author of the biography, American Caesar: Douglas MacArthur, to write that young MacArthur was "a fugitive from his father's relentless love." There is no clear picture as to what happened to Arthur MacArthur, although it is believed that he is still living incognito in New York City. Various people have claimed to observe him visiting the graves of his parents, but those observations have never been confirmed. Others say that he became a concert pianist who performs under different names, preferring to remain in the limelight rather than to be treated as Douglas MacArthur's son.