[2] He studied at Oriel College, Oxford, graduating with a Bachelor of Arts (BA) degree.
[2] On 2 September 1939, Mills became a lieutenant in the National Defence Companies.
[2] From 1941 to 1943, he was commander of the New Forest Group of the Home Guard, and held the rank of colonel.
[7] On 16 June 1918, Mills married Carola Marshall Tuck (1889–1995) at the British Consulate-General in Alexandria, Egypt.
[9] Together they lived at Bisterne Manor in Ringwood, Hampshire and Taverham Hall in Norfolk, and had three sons, including:[2] Mills was knighted in 1958 and died on 2 July 1972.