He represented the Division of Calare (1931–1940) and held ministerial office as Minister for War Service Homes (1934–1936), Defence (1937–1938), Civil Aviation (1938–1939), Health (1940), and Postmaster-General (1940).He was the son of Elizabeth (née Campbell) and Frederick James Thorby; his mother was Irish and his father English.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 Labor Party.In November 1937, Thorby was elected deputy leader of the Country Party, defeating John McEwen by a single vote on the second ballot.He returned to farming on his wife's parents property at Wongarbon and remained active in the Graziers' Association and the Country Party.
Thorby as defence minister speaking with senior army officers