Background
Johnstone was born in Raglan and educated at Auckland Grammar School.
Johnstone was born in Raglan and educated at Auckland Grammar School.
Auckland Grammar School.
He served in the NZEF from 1916 to 1918 and farmed sheep and cattle in the Raglan area. However, he only held the electorate from 5 March to 27 November 1946 as he was defeated by Alan Baxter in the 1946 general election. He held this seat until his retirement in 1963.
In the 1966 New Year Honours, Johnstone was appointed an Officer of the Order of the British Empire for services to farming and in political life.