Educated at St Luke’s, Nembe, St Barnabas’ Town, and at St Joseph’s College, Sasse, near Buea, on the slopes of Mount Cameroon. Here, and at Man-o-War Bay, Victoria, he developed a love of the sea and mountains at a formative age.
He started work as meteorological officer at Ikeja Airport, near Lagos, then joined the Inland Waterways Department as a Marine Officer in training, serving as a cadet on the Elder Dempster ships mv "Sobo" and “Sulima”. He was later transferred to the Nigerian Navy and in 1962 was seconded to the Royal Navy for a series
of courses. He graduated at the Britannia Royal Naval College, Dartmouth, and served with the Royal Navy. On his return to Nigeria in 1966 he held a number of naval posts, including command of the NNS “Enugu”, “Calabar” and “Benin”.
An eager, colourful personality, full of the joy of life and a real sporting enthusiast, keen on driving, yachting, flying, skiing, diving and golf. When he took over as Governor in May 1967, Port Harcourt was on the point of being occupied by the Biafrans. It was not retaken until May 19, 1968, and Commander Diete-Spiff was faced with a war ravaged state, extensive destruction of property, a budgetary deficit and great shortage of qualified personnel. Though many said he was too young for the job, he tackled these problems and by 1972 was able to report that resettlement and rehabilitation were virtually complete.