Macarthur is one of the Stolen Generation (see: Australian Aboriginal and Torres Strait Islander Children) kidnapped under a government policy to destroy Aboriginal civilization. He was raised on the Bungalow mission station near Alice Springs, where his best friend was Charlie Perkins.
He was an extraordinarily fast runner and beat all comers in two states. In spite of this officials refused to choose him for the South Australian touring team unless he paid his own expenses. Macarthur won the national 100 yard title in 1951, but again, because he was Black, he was ignored, this time for selection to the Australian team for the 1952 Helsinki Olympics. The man he beat, Kevan Gosper, was selected instead. (Gosper went on to become a member of the International Olympic Committee and instrumental in the Sydney bid to stage the 2000 Olympics, during which the shameful record of Australian race relations was covered up).
Macarthur emigrated to England and became a professional rugby player, and his club record of tries and goals for the Rochdale Hornets still stands. He returned to Australia and lives in Sydney.