He became a wool-classer, then a seaman and Port Phillip pilot, earning the rank of ship's master in 1938.

[1] Benson joined the Royal Australian Navy during World War II, and commanded the Bathurst-class corvette HMAS Kiama.

[2] Having served as Mayor and Councillor on Williamstown City Council,[3] he was elected to the Australian House of Representatives in 1962 as the Labor member for Batman,[4][5] filling the vacancy formed by the death of Alan Bird.

[6][7] The expulsion arose from Benson's support of continued Australian participation in the Vietnam War, and, more specifically, his refusal to resign from an organisation called the Defend Australia Committee, after it had been proscribed by the Federal Executive.

He was re-elected as an independent in 1966, the first person to achieve this feat in the House of Representatives since Lewis Nott in 1949.