[2] He has a younger sister, Myra who suffered from an illness which resulted in the family's relocating from rural New South Wales to Epping, a northern suburb of Sydney.
[4] After leaving high school, In 1965, Abernethy joined the (then) Petty Sessions Branch of the New South Wales Department of Attorney General and Justice,[2][5] where he worked until he became a Stipendiary Magistrate in 1984.
[7] Following his retirement, Abernethy has commented on the car pursuits by the New South Wales Police Force, arguing in favour of them to prevent the escape of criminals.
[8] In 2005, Abernethy was detected to have exceeded the legal speed limit of 40 km/h while driving in a school zone, resulting in the suspension of his driver's licence.
[9] Although born to and raised in a Presbyterian family, Abernethy left the church as a young man.