He was born at St Pancras in London to chemist Alfred George Mason and Winnie, née Wheeldon.
From 1943 to 1946 he was employed at the Ministry of Supply studying the military applications of quartz crystals, and in 1945 he became an associate member of the Institute of Physics.
He married Sheila Mabelle Clegg at Bournemouth on 7 June 1945. they had three children: Deirdre, Chloe and Paul who were all born in England and who all moved to Sydney, Australia.
From 1983 to 1986 he convened the advisory council of the Australian Broadcasting Corporation (ABC), and he remained active in pacifist causes, notably Scientists Against Nuclear Arms.
Macquarie University still runs the general science courses he designed and awards the Peter Mason Prize for outstanding achievement in them annually.