Geoffrey was the youngest son of Brigadier General Sir Ernest Makins, K.B.E., C.B., D.S.O., and his wife Florence Mellor. He was born in East Preston, Sussex.

[His oldest brother, Roger, 1904-1996, was ranked amongst the outstanding Foreign Office figures of the decade following the Second World War. A man of impressive physical stature and considerable personal charm, he presented the archetypal image of the British diplomat. He was created Baron Sherfield in 1964.]

He went to West Downs School, Winchester in 1924. He spent some time out of school in the winter term of 1925, as he arrived in Southampton from Cape Town with his mother on 15 October. He spent Christmas 1927 with his parents in Lisbon.

He followed his two older brothers and his father, to Winchester College. [His second brother died, accidentally, at the age of 17 in September 1923.] He Matriculated in 1934 and read History in which he graduated with a 3rd in 1938.

On going down, Geoffrey joined the 1st Royal Dragoons, the regiment of which his father was Colonel from 1931-1946. The regiment was mechanised shortly after the outbreak of the War and was transferred to the Royal Armoured Corps in 1940.

War Office, 9 September 1942
The King has been graciously pleased to approve the following award in recognition of gallant and distinguished services in the Middle East during the period November 1941 to April 1942
The Military Cross to Lieutenant Geoffrey Ernest Makins (72510), 1st The Royal Dragoons, Royal Armoured Corps (London, S.W.7)

He was wounded in Normandy and died in Birmingham on 4 September 1944.

He is buried in the churchyard of St Nicholas, Rotherfield Greys, Oxfordshire. There is a plaque in the church commemorating his uncle Captain H. Makins, Queens Victoria Rifles who died on 4 November 1915.

He is commemorated on the MCC Roll of Honour

His diaries from 1937-40, correspondence 1916-44 & other papers are deposited in the Bodleian Library, MSS. Sherfield 1-1051.