Knox was born in the Melbourne suburb of Prahran in 1885 and educated at Scotch College Melbourne. He was the son of William Knox, who had been a member of the Victorian Legislative Council between 1897 and 1901, and the member for Kooyong in the House of Representatives.
The City of Knox is named after him. Knox began his working life as an electrical engineer Soon after, he moved to Beaconsfield to establish an orchard.
In 1920 he moved to Ferntree Gully.
He was elected to the Fern Tree Gully Shire Council in 1923. He became Speaker for the Victorian Parliament in 1942 and remained there until 1947.
Between 1945 and 1960 he held the seat of Scoresby.
