Turnbull was born in London and educated at Westminster School and Magdalen College, Oxford, where he studied politics and philosophy.

An "odd job" Turnbull picked up while in Africa at this time was working for the Hollywood producer Sam Spiegel.

[2] After his first trip to Africa, Turnbull traveled to Yellowknife in the Northwest Territories, where he worked as a geologist and gold miner for a year,[3] before he went back to school to obtain another degree.

He remained in Oxford for two years before another field trip to Africa, finally focusing on the Belgian Congo (1957–58) and Uganda.

The Ik were a hunter-gatherer tribe who had been forced to stop moving around ancestral lands, through the seasons, because it now involved the three national borders of Uganda, Kenya and Sudan.

Forced to become stationary in Uganda, and without a knowledge base and culture for survival under such conditions, they failed to thrive, even to the point of starvation and death.

[4] Some of Turnbull's recordings of Mbuti music were commercially released, and his works inspired other ethnomusicological studies, such as those of Simha Arom and Mauro Campagnoli.

In the Congo in 1970, they conducted fieldwork on the Nkumbi circumcision initiation ritual for boys and the Asa myth of origin among the Mbo of the Ituri forest.

[9] In 1989, Turnbull moved to Bloomington, Indiana, to participate in the building of Tibetan Cultural Center with his friend Thupten Jigme Norbu, elder brother of the 14th Dalai Lama.