Background
Thorby was born in the Sydney suburb of Annandale and was educated at Geurie Public School and Sydney Grammar School and worked on his grandparents" farm at Geurie.
Thorby was born in the Sydney suburb of Annandale and was educated at Geurie Public School and Sydney Grammar School and worked on his grandparents" farm at Geurie.
He studied woolclassing, veterinary science and architecture and became a grazier.
After its division into single-member electorates in 1927 he represented Castlereagh for one term to 1930 until his defeat by Joseph Alfred Clark of the Australian Labor Party. He was the Minister for Agriculture and chairman of the Water Conservation and Irrigation Commission in the government of Thomas Bavin from 1927 to 1930, during which construction of the Wyangala Dam commenced, the Burrinjuck Dam was finished and the Hawkesbury Agricultural College was enlarged. He was a Minister without Portfolio from November 1934 to November 1937 in the Lyons government, entitled Assistant Minister for Repatriation (1934-1935), Minister for War Service Homes (1935-1936) and Assistant Minister for Commerce (1935-1937).
In the Lyons and Page Ministry governments, he was Minister for Defence from November 1937 to November 1938 and Minister for Works and Minister for Civil Aviation from November 1938.
During this period he initiated a program of adding annexes to existing factories to accelerate armaments production, but this program failed to spend even budgeted funds. In April 1939, he left the ministry when the Country Party refused to take part in the Menzies government.
With the formation of a coalition government in March 1940, Thorby became Minister for Health and Postmaster-General. After his defeat in 1940 election by Labor"s John Breen, Thorby ran unsuccessfully for the state seat of Dubbo in 1941 and the federal seat of Calare in 1943 election and 1946 election.
Thorby was a member of the three-member electoral district of Wammerawa in the NSW Legislative Assembly from 1922 to 1927 for Country Party.