Born in Pachmarhi, British India, Caccia was educated at Summer Fields School,[1] Eton College and Trinity College, Oxford and won a Blue at rugby union, playing at centre for Oxford in the Varsity match in 1926.

Caccia entered the diplomatic service in 1929 and was posted to Peking and then to Athens and London where, in 1936, he became assistant private secretary to Anthony Eden.

He was back in Athens early in World War II, but was then attached to the staff of Harold Macmillan, Britain's representative at Allied headquarters in North Africa.

The Greek Civil War once again saw him in that country, and by 1945 his services earned him recognition on the Birthday Honours List.

He was knighted in 1950, and was created a life peer with the title Baron Caccia, of Abernant in the County of Brecknock, on 11 May 1965.