He married Lena Elizabeth Wentworth at the Holy Trinity Church in Melbourne on 16 June 1910, and they had one son.
He was appointed Officer of the Order of the British Empire in June 1919 for his administrative accomplishments during and after the war as a deputy assistant adjutant general.
He resumed his duties with the Australian Army Reserve in South Australia and was later transferred to the Staff Corps in October 1920 and held numerous senior positions over the following two decades.
He was promoted to major general in 1937 and advocated the recruitment of militia as the situation deteriorated in Europe.
On 21 July 1956, Hardie died of Parkinson's disease at the Concord Repatriation General Hospital in Sydney, and was cremated.