He was a member of the Australian Labor Party (ALP) and represented the Division of Bass in federal parliament from 1934 to 1949.

His son Lance Barnard also entered federal politics and served as Deputy Prime Minister of Australia in the 1970s.

He joined Tasmanian Government Railways in 1909, progressing from engine-cleaner to fireman to engine-driver, based out of Launceston.

In 1950, Barnard was elected to represent the Tasmanian House of Assembly division of Bass and held it until his death in 1957.

His son Lance Barnard was deputy prime minister in the Whitlam government, while his nephew Eric and grandson Michael were also members of parliament.