After completing high school he enlisted in the Second Australian Imperial Forces for service in the Second World War.

He practised as a barrister and solicitor in the firm of Thomson & Co until 1970 when he was appointed as a Judge of the Local and District Criminal Court of South Australia.

He was Deputy Prior of the Order of St John, Chief Scout in the Northern Territory and chairman of the Forum for Indigenous Studies at the North Australia Research Unit.

[4] In the 1988 film Evil Angels, which was based on the events surrounding the trial, Muirhead was portrayed by the actor Charles 'Bud' Tingwell.

[5] After he retired he was appointed as a Ministerial Adviser to the Council on Veterans Issues, a position he held from 1993–1994.