Graham Aitken qualified at Otago on the eve of the Second World War, and served with the New Zealand forces in the Pacific. He was regarded as a brilliant student, though something of a loner and for some years it was not generally known which direction his career might follow. After the war he gained specialist qualification in surgery and in gynaecology, thereafter returning to Auckland where he established his own private hospital and gynaecological practice. He retained little contact with his former colleagues in the College of Physicians.
Dr Aitken's first marriage to Miss Betty Johnson of Wellington was dissolved. Subsequently, he married Miss Norma Tucker of Wellington who underwent nursing training in New Plymouth and joined the New Zealand Army Nursing Service.