American noted family member, as the only child of General of the Army Douglas MacArthur and Jean MacArthur. He is also the grandson of Lieutenant General Arthur MacArthur, Jr.
Arthur MacArthur IV’s early life was chronicled extensively in the press. His early childhood was spent around the penthouse built for his father atop the Manila Hotel. After the Japanese invasion of the Philippines, Arthur, his mother and his nanny were forced to relocate from the Manila Hotel as bombs fell nearby. They first joined Arthur’s father on Corregidor Island and then were evacuated by PT boat and B-17 Flying Fortress to Brisbane, Australia in March 1942.
Life Magazine made Arthur their cover story in August 1942 and reported on such matters as the boy’s life in Australia, his “curiously mixed-up accent”, his kindergarten routine, and his new tricycle. After the Japanese surrender in 1945, the family moved to Tokyo, from where the United Press agency reported in 1946 that eight-year-old Arthur MacArthur was considered a “musical prodigy”. Arthur’s first meeting with Emperor Hirohito of Japan’s sons, the future Emperor Akihito and Prince Masahito in September 1949, at a swimming meet, was covered by Sir Keith Murdoch’s Adelaide News under the headline “MacArthur’s son and Jap. princes”.
Upon Douglas MacArthur’s dismissal by President Truman, MacArthur flew home with his family on 18 April 1951. Arthur, then aged 13, had never been to the United States. The family’s return to the United States brought intense media scrutiny of the General’s son as well as the father.
MacArthur graduated from Columbia University in 1961, having majored in English.
After graduation, MacArthur avoided the public spotlight. Today he reportedly lives under an assumed name. He remains active in the General Douglas MacArthur Foundation and with the Douglas MacArthur Memorial in Norfolk, Virginia, where his parents are interred.
His father died on 5 April 1964, aged 84, in Washington, D.C. His mother died of natural causes in Lenox Hill Hospital in Manhattan on 22 January 2000 at age 101.

Link to Wikipedia biography