Debenham was born in Bowral, New South Wales, Australia in December 1883, the younger twin and third child of Rev.

He graduated from the University of Sydney with a BA in English and philosophy, then joined the staff at the Anglican Armidale School in New South Wales.

As director of the institute, Debenham, in conjunction with Priestley and one of Shackleton's Endurance scientists, James Wordie, made Cambridge the centre of polar research in Britain.

[1] During World War II he trained service cadets, lectured to Royal Air Force navigators and devised relief-model techniques for briefing commandos.

[2] Debenham was a prolific author; his published works include: "In the Antarctic: Stories of Scott's Last Expedition 1952"; "Antarctica: The story of a continent"; "Discovery and Exploration: An atlas-history of man's journeys into the unknown" (1968); "Kalahari Sand"; "Nyasaland"; "The way to Ilala"; "Study of African Swamp"; "Simple Surveying"; "The use of Geography"; "Map Making"; "The World is Round"; "Space: The Global Atlas".