Col. John Deng Reng Deng was born in 1919 in a small South Sudanese village called Pachot to father Reng Deng from the Adhiok Clan and mother Aluong Ngon Deng Mayen from the Dachuek clan.
For Dinka people, life in the nineteenth century consisted mainly of cattle herding, cultivation, and small-scale fishing along the banks of the Nile. John began study at Yith Manyok Primary School, which was established by Bishop Machuor, the early British missionary, in 1940; missionaries built schools and wells (“yith” in Dinka language), and they preached the word of God to people in the region.
John was taught Dinka vowels by Reng Arok Reng from the Nyarweng clan and Manyang Atem Aweng from the Pakeer clan. His head teacher, Daniel Deng Atong, was from the Mundari tribe and was, according to Bishop Machuor, a special gift from God, having found an abandoned child floating on the water and taken him in to raise as his own.
John travelled aboard the Lady Baker to Khartoum, the capital of Sudan, to take Apatdit, his sister, for treatment in 1946; Apatdit later returned to Malakal and worked as a nurse, leaving John in Khartoum, where he stayed at Omdurman’s Civil Hospital Compound.
John began adult education with the Catholic Missionary School, led by Mahmoud Ahmed Nasir as its headteacher. John obtained a job as a hospital clerk with a basic salary of 20 dinari, and he spent four years in medical school, after which his cohort was split into groups of five, distributed to Malakal, Wau, and Juba. John remained in Khartoum after training as a medical practitioner. He took 30 days’ leave, excluding 15 days of travel to return to Bor District in 1961. He was then transferred to Wau.
In Wau, John worked with the Red Cross, and in 1962, he moved to Chad, where he worked for three years to vaccinate local people at the border towns against smallpox, whooping cough, and measles. He then returned to Wau headquarters and worked with the chief inspector of Wau Hospital, Dr Hassan. They were taken to the Bhar el Arab area for a year before John was transferred to Yirol, where there were reported cases of pilus, to work with Dr Mohammed Hassan.
John ordered mass penicillin vaccination and established hygiene awareness, helping many people. He remained in Bhar el Ghazel until 1963 when floods struck Bor District. Tensions started to grow as the government ordered the killings of South Sudanese people. John decided to go to Wau to collect medicine, and upon his arrival, he was stopped by Arab soldiers, a sergeant advising him to leave Wau immediately. John left Wau before the mass killing there, arriving in Rumbek after its own mass killing and continuing to Akot to be with his family.