
Benjamin Macdonald joined Macdonald Hamilton & Co Ltd in 1952, retiring in 1985 as joint managing director of the company.
Since 1985, he has served as a director of several Australian public companies including Perpetual Trustees Australia, AMP Society, CSR, Placer Pacific, Allgas Energy, Bank of Queensland, Casinos Austria International, Queensland Cotton Holdings, FKP and AP Eagers. Mr Macdonald was a founding director and deputy chair of Brisbane's FM radio station (Four Triple M).
He was the Honorary Consul for Uruguay in Queensland, and served on the committee of the Royal Automobile Club of Queensland and the Salvation Army (Brisbane Division).