He was a member of the New South Wales Legislative Assembly from 1937 to 1938, representing the seat of Woollahra as an independent aligned with the United Australia Party (UAP).
He was the son of Sarah Jane (née Dunn) and William Henry Mason; his father was a shipping master at the Port of Sydney.
[1] Mason attended Fort Street High School and went on to the University of Sydney, graduating Bachelor of Laws in 1913 with first-class honours.
[1] Mason frequently appeared before the High Court of Australia and the Judicial Committee of the Privy Council on appeals cases.
[5] Mason regarded his victory as a vote against preselection, the process by which only a single endorsed candidate would be nominated by the UAP prior to the election.
[4] A coronial inquest concluded the fall was accidental and occurred after he "slipped in a soft patch of soil on the cliff-top immediately above the spot where his body was found".