He was educated at the Harrow School, the Royal Military Academy, Woolwich, and Christ Church, Oxford.
[1] He joined the Indian Civil Service in 1922 at the age of 23, and remained in the ICS until 1947, when the independence of Pakistan took place.
He served as the last British governor of Khyber-Pakhtunkhwa (then called the North-West Frontier Province) of Pakistan from 1948 to 1949.
They had one daughter, Anstice Ann Flux Dundas, born 12 December 1933 in Peshawar.
Flux Dundas died on 29 April 1973 at "Roxwell", his house in Binfield, Berkshire.