The third of four children, Leo Carew grew up in the centre of London, in the shadow of St. Paul’s Cathedral. Inspired by audiobooks, he developed a late interest in reading and began trying his hand at writing soon afterwards.

Carew read Biological Anthropology at Jesus College, Cambridge, after which he pursued a long-standing love of cold and wild places to the High Arctic archipelago of Svalbard - Old Norse for 'The Cold Edge.' Here, he lived in a tent for a year, training and working as an Arctic guide, and subsequently an explorer. This was also when he revisited a novel he had begun at the age of 12, which was rewritten as The Wolf, the first book in his Under the Northern Sky trilogy.

A reluctant return to London followed to pursue a career as an army medic, during which he completed the sequels - The Spider, and The Cuckoo. Carew currently works as a British Army doctor, plotting his next book, and his next expedition to high north, south or altitude.